Device and method for wirelessly transmitting power on basis of reestablishment of out-band communication

ABSTRACT

The present specification relates to a device and method for wirelessly transmitting power on the basis of the reestablishment of out-band communication. The present specification discloses a wireless power receiving device comprising a communication/control circuit configured to carry out the operations of: performing handover from in-band communication using operating frequencies to out-band communication using any frequencies except for the operating frequencies; transmitting power characteristic information to the wireless power transmitting device or receiving power characteristic information from the wireless power transmitting device through the out-band communication before entering a power transmission phase; and saving power state information determined during the power transmission phase. By defining an out-band communication reestablishment protocol for the wireless power transmitting device or wireless power receiving device, it is possible to improve the performance of wireless power transmission throughout-band communication reestablishment that is fast and efficient.

BACKGROUND OF THE DISCLOSURE Field of the disclosure

The present disclosure relates to wireless charge, and moreparticularly, to a method and apparatus for performing a wireless powertransmission based on a reestablishment of an out-band communication.

Related Art

The wireless power transfer (or transmission) technology corresponds toa technology that may wirelessly transfer (or transmit) power between apower source and an electronic device. For example, by allowing thebattery of a wireless device, such as a smartphone or a tablet PC, andso on, to be recharged by simply loading the wireless device on awireless charging pad, the wireless power transfer technique may providemore outstanding mobility, convenience, and safety as compared to theconventional wired charging environment, which uses a wired chargingconnector. Apart from the wireless charging of wireless devices, thewireless power transfer technique is raising attention as a replacementfor the conventional wired power transfer environment in diverse fields,such as electric vehicles, Bluetooth earphones, 3D glasses, diversewearable devices, household (or home) electric appliances, furniture,underground facilities, buildings, medical equipment, robots, leisure,and so on.

The wireless power transfer (or transmission) method is also referred toas a contactless power transfer method, or a no point of contact powertransfer method, or a wireless charging method. A wireless powertransfer system may be configured of a wireless power transmittersupplying electric energy by using a wireless power transfer method, anda wireless power receiver receiving the electric energy being suppliedby the wireless power transmitter and supplying the receiving electricenergy to a receiver, such as a battery cell, and so on.

The wireless power transfer technique includes diverse methods, such asa method of transferring power by using magnetic coupling, a method oftransferring power by using radio frequency (RF), a method oftransferring power by using microwaves, and a method of transferringpower by using ultrasound (or ultrasonic waves). The method that isbased on magnetic coupling is categorized as a magnetic induction methodand a magnetic resonance method. The magnetic induction methodcorresponds to a method transmitting power by using electric currentsthat are induced to the coil of the receiver by a magnetic field, whichis generated from a coil battery cell of the transmitter, in accordancewith an electromagnetic coupling between a transmitting coil and areceiving coil. The magnetic resonance method is similar to the magneticinduction method in that is uses a magnetic field. However, the magneticresonance method is different from the magnetic induction method in thatenergy is transmitted due to a concentration of magnetic fields on botha transmitting end and a receiving end, which is caused by the generatedresonance.

In the conventional wireless power transmission system, in general,communication between a wireless power transmission apparatus and awireless power reception apparatus uses an amplitude shift keying (ASK)scheme using a magnetic field change and a frequency shift keying (FSK)scheme using a frequency change. Recently, for a large amount of datatransmission such as a middle-power level transmission required in anevolved wireless power transmission system or an authentication, anout-band communication is proposed. The out-band communication maysupport various applications of the wireless power transmission.

However, in the case that an out-band communication is disconnected orreleased while a wireless power transmission is performed based on theout-band communication, a protocol for performing a reestablishment ofthe out-band communication has not been specified yet. Accordingly, amethod and apparatus for a wireless power transmission and a method andapparatus for a wireless power reception for performing areestablishment of the out-band communication are in demand.

SUMMARY

The present disclosure provides a method and apparatus for a wirelesspower transmission and a method and apparatus for a wireless powerreception that support a reestablishment of an out-band communication.

The present disclosure also provides a method and apparatus for awireless power transmission and a method and apparatus for a wirelesspower reception that support a fast and efficient reconnection of BLE.

The present disclosure also provides a method and apparatus for awireless power transmission and a method and apparatus for a wirelesspower reception that perform a reestablishment of a BLE connectionefficiently by saving information previously exchanged when a BLEconnection is disconnected or released.

In an aspect of the present disclosure, provided is a wireless powerreceiver that receives wireless power based on an out-bandcommunication. The apparatus may include a power pickup circuitconfigured to receive wireless power from a wireless power transmitterbased on magnetic coupling with the wireless power transmitter in anoperation frequency and transform an alternate current (AC) signalgenerated by the wireless power to a direct current (DC) signal; acommunication/control circuit configured to be provided with the DCsignal from the power pickup circuit, perform a handover to the out-bandcommunication using a frequency except the operating frequency in anin-band communication using the operation frequency, transmit powercharacteristic information to the wireless power transmitter or receivethe power characteristic information from the wireless power receiverbased on the out-band communication before entering a power transferphase, and perform a process of saving power state informationdetermined during the power transfer phase; and a load configured toreceive the direct current from the power pickup circuit.

In an aspect, the out-band communication is Bluetooth low energy (BLE),and the communication/control circuit transmit or receive the powercharacteristic information based on a generic attribute profile (GATT)of the BLE.

In another aspect, the process of saving the power state informationincludes receiving, by the communication/control circuit, a save requestmessage for requesting a saving of the power state information based onthe out-band communication from the wireless power transmitter; andtransmitting a save response message for identifying the saving of thepower state information to the wireless power transmitter based on theout-band communication.

In still another aspect, the communication/control circuit includes anin-band communication module configured to perform the in-bandcommunication and an out-band communication module configured to performthe out-band communication, and the out-band communication moduletransfers the power state information to the in-band communicationmodule based on the save response message of power information.

In still another aspect, the save request message includes at least oneof device ID information, device address information, power levelinformation, and a public key.

In still another aspect, the communication/control circuit is configuredto perform a process of exchanging the power state information with thewireless power transmitter in a reconnection after a disconnection ofthe out-band communication.

In still another aspect, the process of exchanging the power stateinformation includes receiving, by the communication/control circuit, apower information request message from the wireless power transmitter;transmitting a power information response message to the wireless powertransmitter; and performing a power calibration.

In still another aspect, the power information response message includesat least one of device ID information, device address information, powerlevel information, and a public key.

In still another aspect, the process of exchanging the power stateinformation further includes changing, by the communication/controlcircuit, a power contract by performing a renegotiation phase with thewireless power transmitter based on the out-band communication.

In still another aspect, the communication/control circuit is configuredto perform a process of saving updated power state information duringthe renegotiation phase.

In another aspect of the present disclosure, a wireless powertransmitter performing an authentication based on an out-bandcommunication is provided. The apparatus may include a power conversioncircuit configured to transmit wireless power to a wireless powerreceiver based on magnetic coupling with the wireless power receiver inan operation frequency; and a communication/control circuit configuredto perform a handover to the out-band communication using a frequencyexcept the operating frequency in an in-band communication using theoperation frequency, receive power characteristic information from thewireless power receiver or transmit power characteristic information tothe wireless power receiver based on the out-band communication beforeentering a power transfer phase, and perform a process of saving powerstate information determined during the power transfer phase.

In an aspect, the out-band communication may be Bluetooth low energy(BLE), and the communication/control circuit may transmit or receive thepower characteristic information based on a generic attribute profile(GATT) of the BLE.

In another aspect, the process of saving the power state information mayinclude transmitting, by the communication/control circuit, a saverequest message for requesting a saving of the power state informationbased on the out-band communication to the wireless power receiver; andreceiving a save response message for identifying the saving of thepower state information from the wireless power receiver based on theout-band communication.

In still another aspect, the communication/control circuit may includean in-band communication module configured to perform the in-bandcommunication and an out-band communication module configured to performthe out-band communication, and the out-band communication module maytransfer the power state information to the in-band communication modulebased on the save response message of power information.

In still another aspect, the save request message may include at leastone of device ID information, device address information, power levelinformation, and a public key.

In still another aspect, the communication/control circuit may beconfigured to perform a process of exchanging the power stateinformation with the wireless power receiver in a reconnection after adisconnection of the out-band communication.

In still another aspect, the process of exchanging the power stateinformation may include transmitting, by the communication/controlcircuit, a power information request message to the wireless powerreceiver; receiving a power information response message from thewireless power receiver; and performing a power calibration.

In still another aspect, the power information response message mayinclude at least one of device ID information, device addressinformation, power level information, and a public key.

In still another aspect, the process of exchanging the power stateinformation may further include changing, by the communication/controlcircuit, a power contract by performing a renegotiation phase with thewireless power receiver based on the out-band communication.

In still another aspect, the communication/control circuit may beconfigured to perform a process of saving updated power stateinformation during the renegotiation phase.

Advantageous Effects

A protocol for a reestablishment of an out-band communication of awireless power transmission apparatus and a wireless power receptionapparatus is defined, and the performance of wireless power transmissionmay be improved based on a fast and efficient reestablishment of theout-band communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

FIG. 2 is a block diagram of a wireless power system (10) according toanother exemplary embodiment of the present disclosure.

FIG. 3a shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system.

FIG. 3b shows an example of a WPC NDEF in a wireless power transfersystem.

FIG. 4a is a block diagram of a wireless power transfer system accordingto another exemplary embodiment of the present disclosure.

FIG. 4b is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

FIG. 4c is a block diagram illustrating a wireless power transfer systemusing BLE communication according to an example.

FIG. 4d is a block diagram illustrating a wireless power transfer systemusing BLE communication according to another example.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present disclosure.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

FIG. 12 illustrates a data expression, an operation form, and a systemarchitecture of BLE.

FIG. 13 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a BLE reconnection by the wirelesspower transmission apparatus and the wireless power reception apparatusaccording to an example.

FIG. 14 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a BLE reconnection by the wirelesspower transmission apparatus and the wireless power reception apparatusaccording to another example.

FIG. 15 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a process of saving the power stateinformation by the wireless power transmission apparatus and thewireless power reception apparatus according to an example.

FIG. 16 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a process of automatic reconnection ofthe out-band communication by the wireless power transmission apparatusand the wireless power reception apparatus according to an example.

FIG. 17 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a process of automatic reconnection ofthe out-band communication by the wireless power transmission apparatusand the wireless power reception apparatus according to another example.

FIG. 18 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a process of automatic reconnection ofthe out-band communication by the wireless power transmission apparatusand the wireless power reception apparatus according to still anotherexample.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

The term “wireless power”, which will hereinafter be used in thisspecification, will be used to refer to an arbitrary form of energy thatis related to an electric field, a magnetic field, and anelectromagnetic field, which is transferred (or transmitted) from awireless power transmitter to a wireless power receiver without usingany physical electromagnetic conductors. The wireless power may also bereferred to as a wireless power signal, and this may refer to anoscillating magnetic flux that is enclosed by a primary coil and asecondary coil. For example, power conversion for wirelessly chargingdevices including mobile phones, cordless phones, iPods, MP3 players,headsets, and so on, within the system will be described in thisspecification. Generally, the basic principle of the wireless powertransfer technique includes, for example, all of a method oftransferring power by using magnetic coupling, a method of transferringpower by using radio frequency (RF), a method of transferring power byusing microwaves, and a method of transferring power by using ultrasound(or ultrasonic waves).

FIG. 1 is a block diagram of a wireless power system (10) according toan exemplary embodiment of the present disclosure.

Referring to FIG. 1, the wireless power system (10) include a wirelesspower transmitter (100) and a wireless power receiver (200).

The wireless power transmitter (100) is supplied with power from anexternal power source (S) and generates a magnetic field. The wirelesspower receiver (200) generates electric currents by using the generatedmagnetic field, thereby being capable of wirelessly receiving power.

Additionally, in the wireless power system (10), the wireless powertransmitter (100) and the wireless power receiver (200) may transceive(transmit and/or receive) diverse information that is required for thewireless power transfer. Herein, communication between the wirelesspower transmitter (100) and the wireless power receiver (200) may beperformed (or established) in accordance with any one of an in-bandcommunication, which uses a magnetic field that is used for the wirelesspower transfer (or transmission), and an out-band communication, whichuses a separate communication carrier. Out-band communication may alsobe referred to as out-of-band communication. Hereinafter, out-bandcommunication will be largely described. Examples of out-bandcommunication may include NFC, Bluetooth, Bluetooth low energy (BLE),and the like.

Herein, the wireless power transmitter (100) may be provided as a fixedtype or a mobile (or portable) type. Examples of the fixed transmittertype may include an embedded type, which is embedded in in-door ceilingsor wall surfaces or embedded in furniture, such as tables, an implantedtype, which is installed in out-door parking lots, bus stops, subwaystations, and so on, or being installed in means of transportation, suchas vehicles or trains. The mobile (or portable) type wireless powertransmitter (100) may be implemented as a part of another device, suchas a mobile device having a portable size or weight or a cover of alaptop computer, and so on.

Additionally, the wireless power receiver (200) should be interpreted asa comprehensive concept including diverse home appliances and devicesthat are operated by being wirelessly supplied with power instead ofdiverse electronic devices being equipped with a battery and a powercable. Typical examples of the wireless power receiver (200) may includeportable terminals, cellular phones, smartphones, personal digitalassistants (PDAs), portable media players (PDPs), Wibro terminals,tablet PCs, phablet, laptop computers, digital cameras, navigationterminals, television, electronic vehicles (EVs), and so on.

In the wireless power system (10), one wireless power receiver (200) ora plurality of wireless power receivers may exist. Although it is shownin FIG. 1 that the wireless power transmitter (100) and the wirelesspower receiver (200) send and receive power to and from one another in aone-to-one correspondence (or relationship), as shown in FIG. 2, it isalso possible for one wireless power transmitter (100) to simultaneouslytransfer power to multiple wireless power receivers (200-1, 200-2, . . ., 200-M). Most particularly, in case the wireless power transfer (ortransmission) is performed by using a magnetic resonance method, onewireless power transmitter (100) may transfer power to multiple wirelesspower receivers (200-1, 200-2, . . . , 200-M) by using a synchronizedtransport (or transfer) method or a time-division transport (ortransfer) method.

Additionally, although it is shown in FIG. 1 that the wireless powertransmitter (100) directly transfers (or transmits) power to thewireless power receiver (200), the wireless power system (10) may alsobe equipped with a separate wireless power transceiver, such as a relayor repeater, for increasing a wireless power transport distance betweenthe wireless power transmitter (100) and the wireless power receiver(200). In this case, power is delivered to the wireless powertransceiver from the wireless power transmitter (100), and, then, thewireless power transceiver may transfer the received power to thewireless power receiver (200).

Hereinafter, the terms wireless power receiver, power receiver, andreceiver, which are mentioned in this specification, will refer to thewireless power receiver (200). Also, the terms wireless powertransmitter, power transmitter, and transmitter, which are mentioned inthis specification, will refer to the wireless power transmitter (100).

FIG. 3 shows an exemplary embodiment of diverse electronic devicesadopting a wireless power transfer system.

As shown in FIG. 3, the electronic devices included in the wirelesspower transfer system are sorted in accordance with the amount oftransmitted power and the amount of received power. Referring to FIG. 3,wearable devices, such as smart watches, smart glasses, head mounteddisplays (HMDs), smart rings, and so on, and mobile electronic devices(or portable electronic devices), such as earphones, remote controllers,smartphones, PDAs, tablet PCs, and so on, may adopt a low-power(approximately 5 W or less or approximately 20 W or less) wirelesscharging method.

Small-sized/Mid-sized electronic devices, such as laptop computers,robot vacuum cleaners, TV receivers, audio devices, vacuum cleaners,monitors, and so on, may adopt a mid-power (approximately 50 W or lessor approximately 200 W or less) wireless charging method. Kitchenappliances, such as mixers, microwave ovens, electric rice cookers, andso on, and personal transportation devices (or other electric devices ormeans of transportation), such as powered wheelchairs, powered kickscooters, powered bicycles, electric cars, and so on may adopt ahigh-power (approximately 2 kW or less or approximately 22 kW or less)wireless charging method.

The electric devices or means of transportation, which are describedabove (or shown in FIG. 1) may each include a wireless power receiver,which will hereinafter be described in detail. Therefore, theabove-described electric devices or means of transportation may becharged (or re-charged) by wirelessly receiving power from a wirelesspower transmitter.

Hereinafter, although the present disclosure will be described based ona mobile device adopting the wireless power charging method, this ismerely exemplary. And, therefore, it shall be understood that thewireless charging method according to the present disclosure may beapplied to diverse electronic devices.

A standard for the wireless power transfer (or transmission) includes awireless power consortium (WPC), an air fuel alliance (AFA), and a powermatters alliance (PMA).

The WPC standard defines a baseline power profile (BPP) and an extendedpower profile (EPP). The BPP is related to a wireless power transmitterand a wireless power receiver supporting a power transfer of 5 W, andthe EPP is related to a wireless power transmitter and a wireless powerreceiver supporting the transfer of a power range greater than 5 W andless than 30 W.

Diverse wireless power transmitters and wireless power receivers eachusing a different power level may be covered by each standard and may besorted by different power classes or categories.

For example, the WPC may categorize (or sort) the wireless powertransmitters and the wireless power receivers as PC-1, PC0, PC1, andPC2, and the WPC may provide a standard document (or specification) foreach power class (PC). The PC-1 standard relates to wireless powertransmitters and receivers providing a guaranteed power of less than 5W. The application of PC-1 includes wearable devices, such as smartwatches.

The PC0 standard relates to wireless power transmitters and receiversproviding a guaranteed power of 5 W. The PC0 standard includes an EPPhaving a guaranteed power ranges that extends to 30 W. Although in-band(IB) communication corresponds to a mandatory communication protocol ofPC0, out-of-band (OB) communication that is used as an optional backupchannel may also be used for PC0. The wireless power receiver may beidentified by setting up an OB flag, which indicates whether or not theOB is supported, within a configuration packet. A wireless powertransmitter supporting the OB may enter an OB handover phase bytransmitting a bit-pattern for an OB handover as a response to theconfiguration packet. The response to the configuration packet maycorrespond to an NAK, an ND, or an 8-bit pattern that is newly defined.The application of the PC0 includes smartphones.

The PC1 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 30 W to 150 W. OB correspondsto a mandatory communication channel for PC1, and IB is used forinitialization and link establishment to OB. The wireless powertransmitter may enter an OB handover phase by transmitting a bit-patternfor an OB handover as a response to the configuration packet. Theapplication of the PC1 includes laptop computers or power tools.

The PC2 standard relates to wireless power transmitters and receiversproviding a guaranteed power ranging from 200 W to 2 kW, and itsapplication includes kitchen appliances.

As described above, the PCs may be differentiated in accordance with therespective power levels. And, information on whether or not thecompatibility between the same PCs is supported may be optional ormandatory. Herein, the compatibility between the same PCs indicates thatpower transfer/reception between the same PCs is possible. For example,in case a wireless power transmitter corresponding to PC x is capable ofperforming charging of a wireless power receiver having the same PC x,it may be understood that compatibility is maintained between the samePCs. Similarly, compatibility between different PCs may also besupported. Herein, the compatibility between different PCs indicatesthat power transfer/reception between different PCs is also possible.For example, in case a wireless power transmitter corresponding to PC xis capable of performing charging of a wireless power receiver having PCy, it may be understood that compatibility is maintained between thedifferent PCs.

The support of compatibility between PCs corresponds to an extremelyimportant issue in the aspect of user experience and establishment ofinfrastructure. Herein, however, diverse problems, which will bedescribed below, exist in maintaining the compatibility between PCs.

In case of the compatibility between the same PCs, for example, in caseof a wireless power receiver using a lap-top charging method, whereinstable charging is possible only when power is continuously transferred,even if its respective wireless power transmitter has the same PC, itmay be difficult for the corresponding wireless power receiver to stablyreceive power from a wireless power transmitter of the power toolmethod, which transfers power non-continuously. Additionally, in case ofthe compatibility between different PCs, for example, in case a wirelesspower transmitter having a minimum guaranteed power of 200 W transferspower to a wireless power receiver having a maximum guaranteed power of5 W, the corresponding wireless power receiver may be damaged due to anovervoltage. As a result, it may be inappropriate (or difficult) to usethe PS as an index/reference standard representing/indicating thecompatibility.

Wireless power transmitters and receivers may provide a very convenientuser experience and interface (UX/UI). That is, a smart wirelesscharging service may be provided, and the smart wireless chargingservice may be implemented based on a UX/UI of a smartphone including awireless power transmitter. For these applications, an interface betweena processor of a smartphone and a wireless charging receiver allows for“drop and play” two-way communication between the wireless powertransmitter and the wireless power receiver.

As an example, a user may experience a smart wireless charging servicein a hotel. When the user enters a hotel room and puts a smartphone on awireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when it is detectedthat wireless power is received, or when the smartphone receivesinformation on the smart wireless charging service from the wirelesscharger, the smartphone enters a state of inquiring the user aboutagreement (opt-in) of supplemental features. To this end, the smartphonemay display a message on a screen in a manner with or without an alarmsound. An example of the message may include the phrase “Welcome to ###hotel. Select “Yes” to activate smart charging functions: Yes|NoThanks.” The smartphone receives an input from the user who selects Yesor No Thanks, and performs a next procedure selected by the user. If Yesis selected, the smartphone transmits corresponding information to thewireless charger. The smartphone and the wireless charger perform thesmart charging function together.

The smart wireless charging service may also include receiving WiFicredentials auto-filled. For example, the wireless charger transmits theWiFi credentials to the smartphone, and the smartphone automaticallyinputs the WiFi credentials received from the wireless charger byrunning an appropriate application.

The smart wireless charging service may also include running a hotelapplication that provides hotel promotions or obtaining remotecheck-in/check-out and contact information.

As another example, the user may experience the smart wireless chargingservice in a vehicle. When the user gets in the vehicle and puts thesmartphone on the wireless charger, the wireless charger transmitswireless power to the smartphone and the smartphone receives wirelesspower. In this process, the wireless charger transmits information onthe smart wireless charging service to the smartphone. When it isdetected that the smartphone is located on the wireless charger, whenwireless power is detected to be received, or when the smartphonereceives information on the smart wireless charging service from thewireless charger, the smartphone enters a state of inquiring the userabout checking identity.

In this state, the smartphone is automatically connected to the vehiclevia WiFi and/or Bluetooth. The smartphone may display a message on thescreen in a manner with or without an alarm sound. An example of themessage may include a phrase of “Welcome to your car. Select “Yes” tosynch device with in-car controls: Yes|No Thanks.” Upon receiving theuser's input to select Yes or No Thanks, the smartphone performs a nextprocedure selected by the user. If Yes is selected, the smartphonetransmits corresponding information to the wireless charger. Inaddition, the smartphone and the wireless charger may run an in-vehiclesmart control function together by driving in-vehicleapplication/display software. The user may enjoy the desired music andcheck a regular map location. The in-vehicle applications/displaysoftware may include an ability to provide synchronous access forpassers-by.

As another example, the user may experience smart wireless charging athome. When the user enters the room and puts the smartphone on thewireless charger in the room, the wireless charger transmits wirelesspower to the smartphone and the smartphone receives wireless power. Inthis process, the wireless charger transmits information on the smartwireless charging service to the smartphone. When it is detected thatthe smartphone is located on the wireless charger, when wireless poweris detected to be received, or when the smartphone receives informationon the smart wireless charging service from the wireless charger, thesmartphone enters a state of inquiring the user about agreement (opt-in)of supplemental features. To this end, the smartphone may display amessage on the screen in a manner with or without an alarm sound. Anexample of the message may include a phrase such as “Hi xxx, Would youlike to activate night mode and secure the building?: Yes|No Thanks.”The smartphone receives a user input to select Yes or No Thanks andperforms a next procedure selected by the user. If Yes is selected, thesmartphone transmits corresponding information to the wireless charger.The smartphones and the wireless charger may recognize at least user'spattern and recommend the user to lock doors and windows, turn offlights, or set an alarm.

Hereinafter, ‘profiles’ will be newly defined based on indexes/referencestandards representing/indicating the compatibility. More specifically,it may be understood that by maintaining compatibility between wirelesspower transmitters and receivers having the same ‘profile’, stable powertransfer/reception may be performed, and that power transfer/receptionbetween wireless power transmitters and receivers having different‘profiles’ cannot be performed. The ‘profiles’ may be defined inaccordance with whether or not compatibility is possible and/or theapplication regardless of (or independent from) the power class.

For example, the profile may be sorted into 3 different categories, suchas i) Mobile, ii) Power tool and iii) Kitchen.

For another example, the profile may be sorted into 4 differentcategories, such as i) Mobile, ii) Power tool, iii) Kitchen, and iv)Wearable.

In case of the ‘Mobile’ profile, the PC may be defined as PC0 and/orPC1, the communication protocol/method may be defined as IB and OBcommunication, and the operation frequency may be defined as 87 to 205kHz, and smartphones, laptop computers, and so on, may exist as theexemplary application.

In case of the ‘Power tool’ profile, the PC may be defined as PC1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 145 kHz, and powertools, and so on, may exist as the exemplary application.

In case of the ‘Kitchen’ profile, the PC may be defined as PC2, thecommunication protocol/method may be defined as NFC-based communication,and the operation frequency may be defined as less than 100 kHz, andkitchen/home appliances, and so on, may exist as the exemplaryapplication.

In the case of power tools and kitchen profiles, NFC communication maybe used between the wireless power transmitter and the wireless powerreceiver. The wireless power transmitter and the wireless power receivermay confirm that they are NFC devices with each other by exchanging WPCNFC data exchange profile format (NDEF). For example, the WPC NDEF mayinclude an application profile field (e.g., 1B), a version field (e.g.,1B), and profile specific data (e.g., 1B). The application profile fieldindicates whether the corresponding device is i) mobile and computing,ii) power tool, and iii) kitchen, and an upper nibble in the versionfield indicates a major version and a lower nibble indicates a minorversion. In addition, profile-specific data defines content for thekitchen.

In case of the ‘Wearable’ profile, the PC may be defined as PC-1, thecommunication protocol/method may be defined as IB communication, andthe operation frequency may be defined as 87 to 205 kHz, and wearabledevices that are worn by the users, and so on, may exist as theexemplary application.

It may be mandatory to maintain compatibility between the same profiles,and it may be optional to maintain compatibility between differentprofiles.

The above-described profiles (Mobile profile, Power tool profile,Kitchen profile, and Wearable profile) may be generalized and expressedas first to nth profile, and a new profile may be added/replaced inaccordance with the WPC standard and the exemplary embodiment.

In case the profile is defined as described above, the wireless powertransmitter may optionally perform power transfer only to the wirelesspower receiving corresponding to the same profile as the wireless powertransmitter, thereby being capable of performing a more stable powertransfer. Additionally, since the load (or burden) of the wireless powertransmitter may be reduced and power transfer is not attempted to awireless power receiver for which compatibility is not possible, therisk of damage in the wireless power receiver may be reduced.

PC1 of the ‘Mobile’ profile may be defined by being derived from anoptional extension, such as OB, based on PC0. And, the ‘Power tool’profile may be defined as a simply modified version of the PC1 ‘Mobile’profile. Additionally, up until now, although the profiles have beendefined for the purpose of maintaining compatibility between the sameprofiles, in the future, the technology may be evolved to a level ofmaintaining compatibility between different profiles. The wireless powertransmitter or the wireless power receiver may notify (or announce) itsprofile to its counterpart by using diverse methods.

In the AFA standard, the wireless power transmitter is referred to as apower transmitting unit (PTU), and the wireless power receiver isreferred to as a power receiving unit (PRU). And, the PTU is categorizedto multiple classes, as shown in Table 1, and the PRU is categorized tomultiple classes, as shown in Table 2.

TABLE 1 Minimum value for a Minimum category maximum number of PTUP_(TX) _(—) _(IN) _(—) _(MAX) support requirement supported devicesClass 1  2 W 1x Category 1 1x Category 1 Class 2 10 W 1x Category 3 2xCategory 2 Class 3 16 W 1x Category 4 2x Category 3 Class 4 33 W 1xCategory 5 3x Category 3 Class 5 50 W 1x Category 6 4x Category 3 Class6 70 W 1x Category 7 5x Category 3

TABLE 2 PRU P_(RX) _(—) _(OUT) _(—) _(MAX′) Exemplary applicationCategory 1 TBD Bluetooth headset Category 2 3.5 W Feature phone Category3 6.5 W Smartphone Category 4 13 W Tablet PC, Phablet Category 5 25 WSmall form factor laptop Category 6 37.5 W General laptop Category 7 50W Home appliance

As shown in Table 1, a maximum output power capability of Class n PTUmay be equal to or greater than the P_(TX_IN_MAX) of the correspondingclass. The PRU cannot draw a power that is higher than the power levelspecified in the corresponding category.

FIG. 4a is a block diagram of a wireless power transfer system accordingto another exemplary embodiment of the present disclosure.

Referring to FIG. 4 a, the wireless power transfer system (10) includesa mobile device (450), which wirelessly receives power, and a basestation (400), which wirelessly transmits power.

As a device providing induction power or resonance power, the basestation (400) may include at least one of a wireless power transmitter(100) and a system unit (405). The wireless power transmitter (100) maytransmit induction power or resonance power and may control thetransmission. The wireless power transmitter (100) may include a powerconversion circuit (110) converting electric energy to a power signal bygenerating a magnetic field through a primary coil (or primary coils),and a communications & control circuit (120) controlling thecommunication and power transfer between the wireless power receiver(200) in order to transfer power at an appropriate (or suitable) level.The system circuit (405) may perform input power provisioning,controlling of multiple wireless power transmitters, and other operationcontrols of the base station (400), such as user interface control.

The primary coil may generate an electromagnetic field by using analternating current power (or voltage or current). The primary coil issupplied with an alternating current power (or voltage or current) of aspecific frequency, which is being outputted from the power conversioncircuit (110). And, accordingly, the primary coil may generate amagnetic field of the specific frequency. The magnetic field may begenerated in a non-radial shape or a radial shape. And, the wirelesspower receiver (200) receives the generated magnetic field and thengenerates an electric current. In other words, the primary coilwirelessly transmits power.

In the magnetic induction method, a primary coil and a secondary coilmay have randomly appropriate shapes. For example, the primary coil andthe secondary coil may correspond to copper wire being wound around ahigh-permeability formation, such as ferrite or a non-crystalline metal.The primary coil may also be referred to as a transmitting coil, aprimary core, a primary winding, a primary loop antenna, and so on.Meanwhile, the secondary coil may also be referred to as a receivingcoil, a secondary core, a secondary winding, a secondary loop antenna, apickup antenna, and so on.

In case of using the magnetic resonance method, the primary coil and thesecondary coil may each be provided in the form of a primary resonanceantenna and a secondary resonance antenna. The resonance antenna mayhave a resonance structure including a coil and a capacitor. At thispoint, the resonance frequency of the resonance antenna may bedetermined by the inductance of the coil and a capacitance of thecapacitor. Herein, the coil may be formed to have a loop shape. And, acore may be placed inside the loop. The core may include a physicalcore, such as a ferrite core, or an air core.

The energy transmission (or transfer) between the primary resonanceantenna and the second resonance antenna may be performed by a resonancephenomenon occurring in the magnetic field. When a near fieldcorresponding to a resonance frequency occurs in a resonance antenna,and in case another resonance antenna exists near the correspondingresonance antenna, the resonance phenomenon refers to a highly efficientenergy transfer occurring between the two resonance antennas that arecoupled with one another. When a magnetic field corresponding to theresonance frequency is generated between the primary resonance antennaand the secondary resonance antenna, the primary resonance antenna andthe secondary resonance antenna resonate with one another. And,accordingly, in a general case, the magnetic field is focused toward thesecond resonance antenna at a higher efficiency as compared to a casewhere the magnetic field that is generated from the primary antenna isradiated to a free space. And, therefore, energy may be transferred tothe second resonance antenna from the first resonance antenna at a highefficiency. The magnetic induction method may be implemented similarlyto the magnetic resonance method. However, in this case, the frequencyof the magnetic field is not required to be a resonance frequency.Nevertheless, in the magnetic induction method, the loops configuringthe primary coil and the secondary coil are required to match oneanother, and the distance between the loops should be very close-ranged.

Although it is not shown in the drawing, the wireless power transmitter(100) may further include a communication antenna. The communicationantenna may transmit and/or receive a communication signal by using acommunication carrier apart from the magnetic field communication. Forexample, the communication antenna may transmit and/or receivecommunication signals corresponding to Wi-Fi, Bluetooth, Bluetooth LE,ZigBee, NFC, and so on.

The communications & control circuit (120) may transmit and/or receiveinformation to and from the wireless power receiver (200). Thecommunications & control circuit (120) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control circuit (120) mayperform in-band (IB) communication by transmitting information on themagnetic wave through the primary coil or by receiving information onthe magnetic wave through the primary coil. At this point, thecommunications & control circuit (120) may load information in themagnetic wave or may interpret the information that is carried by themagnetic wave by using a modulation scheme, such as binary phase shiftkeying (BPSK) or amplitude shift keying (ASK), and so on, or a codingscheme, such as Manchester coding or non-return-to-zero level (NZR-L)coding, and so on. By using the above-described IB communication, thecommunications & control circuit (120) may transmit and/or receiveinformation to distances of up to several meters at a data transmissionrate of several kbps.

The OB communication module may perform out-of-band communicationthrough a communication antenna. For example, the communications &control circuit (120) may be provided to a near field communicationmodule. Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control circuit (120) may control the overalloperations of the wireless power transmitter (100). The communications &control circuit (120) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power transmitter (100).

The communications & control circuit (120) may be implemented in acomputer or a similar device as hardware, software, or a combination ofthe same. When implemented in the form of hardware, the communications &control circuit (120) may be provided as an electronic circuitperforming control functions by processing electrical signals. And, whenimplemented in the form of software, the communications & controlcircuit (120) may be provided as a program that operates thecommunications & control circuit (120).

By controlling the operating point, the communications & control circuit(120) may control the transmitted power. The operating point that isbeing controlled may correspond to a combination of a frequency (orphase), a duty cycle, a duty ratio, and a voltage amplitude. Thecommunications & control circuit (120) may control the transmitted powerby adjusting any one of the frequency (or phase), the duty cycle, theduty ratio, and the voltage amplitude. Additionally, the wireless powertransmitter (100) may supply a consistent level of power, and thewireless power receiver (200) may control the level of received power bycontrolling the resonance frequency.

The mobile device (450) includes a wireless power receiver (200)receiving wireless power through a secondary coil, and a load (455)receiving and storing the power that is received by the wireless powerreceiver (200) and supplying the received power to the device.

The wireless power receiver (200) may include a power pick-up circuit(210) and a communications & control circuit (220). The power pick-upcircuit (210) may receive wireless power through the secondary coil andmay convert the received wireless power to electric energy. The powerpick-up circuit (210) rectifies the alternating current (AC) signal,which is received through the secondary coil, and converts the rectifiedsignal to a direct current (DC) signal. The communications & controlcircuit (220) may control the transmission and reception of the wirelesspower (transfer and reception of power).

The secondary coil may receive wireless power that is being transmittedfrom the wireless power transmitter (100). The secondary coil mayreceive power by using the magnetic field that is generated in theprimary coil. Herein, in case the specific frequency corresponds aresonance frequency, magnetic resonance may occur between the primarycoil and the secondary coil, thereby allowing power to be transferredwith greater efficiency.

Although it is not shown in FIG. 4 a, the communications & controlcircuit (220) may further include a communication antenna. Thecommunication antenna may transmit and/or receive a communication signalby using a communication carrier apart from the magnetic fieldcommunication. For example, the communication antenna may transmitand/or receive communication signals corresponding to Wi-Fi, Bluetooth,Bluetooth LE, ZigBee, NFC, and so on.

The communications & control circuit (220) may transmit and/or receiveinformation to and from the wireless power transmitter (100). Thecommunications & control circuit (220) may include at least one of an IBcommunication module and an OB communication module.

The IB communication module may transmit and/or receive information byusing a magnetic wave, which uses a specific frequency as its centerfrequency. For example, the communications & control circuit (220) mayperform IB communication by loading information in the magnetic wave andby transmitting the information through the secondary coil or byreceiving the magnetic wave carrying the information through thesecondary coil. At this point, the communications & control circuit(120) may load information in the magnetic wave or may interpret theinformation that is carried by the magnetic wave by using a modulationscheme, such as binary phase shift keying (BPSK) or amplitude shiftkeying (ASK), and so on, or a coding scheme, such as Manchester codingor non-return-to-zero level (NZR-L) coding, and so on. By using theabove-described IB communication, the communications & control circuit(220) may transmit and/or receive information to distances of up toseveral meters at a data transmission rate of several kbps.

The OB communication module may perform out-of-band communicationthrough a communication antenna. For example, the communications &control circuit (220) may be provided to a near field communicationmodule.

Examples of the near field communication module may includecommunication modules, such as Wi-Fi, Bluetooth, Bluetooth LE, ZigBee,NFC, and so on.

The communications & control circuit (220) may control the overalloperations of the wireless power receiver (200). The communications &control circuit (220) may perform calculation and processing of diverseinformation and may also control each configuration element of thewireless power receiver (200).

The communications & control circuit (220) may be implemented in acomputer or a similar device as hardware, software, or a combination ofthe same. When implemented in the form of hardware, the communications &control circuit (220) may be provided as an electronic circuitperforming control functions by processing electrical signals. And, whenimplemented in the form of software, the communications & controlcircuit (220) may be provided as a program that operates thecommunications & control circuit (220).

When the communication/control circuit 120 and the communication/controlcircuit 220 are Bluetooth or Bluetooth LE as an OB communication moduleor a short-range communication module, the communication/control circuit120 and the communication/control circuit 220 may each be implementedand operated with a communication architecture as shown in FIG. 4 b.

FIG. 4b is a diagram illustrating an example of a Bluetoothcommunication architecture to which an embodiment according to thepresent disclosure may be applied.

Referring to FIG. 4 b, (a) of FIG. 4b shows an example of a protocolstack of Bluetooth basic rate (BR)/enhanced data rate (EDR) supportingGATT, and (b) shows an example of Bluetooth low energy (BLE) protocolstack.

Specifically, as shown in (a) of FIG. 4 b, the Bluetooth BR/EDR protocolstack may include an upper control stack 460 and a lower host stack 470based on a host controller interface (HCI) 18.

The host stack (or host module) 470 refers to hardware for transmittingor receiving a Bluetooth packet to or from a wirelesstransmission/reception module which receives a Bluetooth signal of 2.4GHz, and the controller stack 460 is connected to the Bluetooth moduleto control the Bluetooth module and perform an operation.

The host stack 470 may include a BR/EDR PHY layer 12, a BR/EDR basebandlayer 14, and a link manager layer 16.

The BR/EDR PHY layer 12 is a layer that transmits and receives a 2.4 GHzradio signal, and in the case of using Gaussian frequency shift keying(GFSK) modulation, the BR/EDR PHY layer 12 may transmit data by hopping79 RF channels.

The BR/EDR baseband layer 14 serves to transmit a digital signal,selects a channel sequence for hopping 1400 times per second, andtransmits a time slot with a length of 625 us for each channel.

The link manager layer 16 controls an overall operation (link setup,control, security) of Bluetooth connection by utilizing a link managerprotocol (LMP).

The link manager layer 16 may perform the following functions.

Performs ACL/SCO logical transport, logical link setup, and control.

Detach: It interrupts connection and informs a counterpart device abouta reason for the interruption.

Performs power control and role switch.

Performs security (authentication, pairing, encryption) function.

The host controller interface layer 18 provides an interface between ahost module and a controller module so that a host provides commands anddata to the controller and the controller provides events and data tothe host.

The host stack (or host module, 470) includes a logical link control andadaptation protocol (L2CAP) 21, an attribute protocol 22, a genericattribute profile (GATT) 23, a generic access profile (GAP) 24, and aBR/EDR profile 25.

The logical link control and adaptation protocol (L2CAP) 21 may provideone bidirectional channel for transmitting data to a specific protocolor profile.

The L2CAP 21 may multiplex various protocols, profiles, etc., providedfrom upper Bluetooth.

L2CAP of Bluetooth BR/EDR uses dynamic channels, supports protocolservice multiplexer, retransmission, streaming mode, and providessegmentation and reassembly, per-channel flow control, and errorcontrol.

The generic attribute profile (GATT) 23 may be operable as a protocolthat describes how the attribute protocol 22 is used when services areconfigured. For example, the generic attribute profile 23 may beoperable to specify how ATT attributes are grouped together intoservices and may be operable to describe features associated withservices.

Accordingly, the generic attribute profile 23 and the attributeprotocols (ATT) 22 may use features to describe device's state andservices, how features are related to each other, and how they are used.

The attribute protocol 22 and the BR/EDR profile 25 define a service(profile) using Bluetooth BR/EDR and an application protocol forexchanging these data, and the generic access profile (GAP) 24 definesdevice discovery, connectivity, and security level.

As shown in (b) of FIG. 4 b, the Bluetooth LE protocol stack includes acontroller stack 480 operable to process a wireless device interfaceimportant in timing and a host stack 490 operable to process high leveldata.

First, the controller stack 480 may be implemented using a communicationmodule that may include a Bluetooth wireless device, for example, aprocessor module that may include a processing device such as amicroprocessor.

The host stack 490 may be implemented as a part of an OS running on aprocessor module or as an instantiation of a package on the OS.

In some cases, the controller stack and the host stack may be run orexecuted on the same processing device in a processor module.

The controller stack 480 includes a physical layer (PHY) 32, a linklayer 34, and a host controller interface 36.

The physical layer (PHY, wireless transmission/reception module) 32 is alayer that transmits and receives a 2.4 GHz radio signal and usesGaussian frequency shift keying (GFSK) modulation and a frequencyhopping scheme including 40 RF channels.

The link layer 34, which serves to transmit or receive Bluetoothpackets, creates connections between devices after performingadvertising and scanning functions using 3 advertising channels andprovides a function of exchanging data packets of up to 257 bytesthrough 37 data channels.

The host stack includes a generic access profile (GAP) 45, a logicallink control and adaptation protocol (L2CAP, 41), a security manager(SM) 42, and an attribute protocol (ATT) 43, a generic attribute profile(GATT) 44, a generic access profile 45, and an LE profile 46. However,the host stack 490 is not limited thereto and may include variousprotocols and profiles.

The host stack multiplexes various protocols, profiles, etc., providedfrom upper Bluetooth using L2CAP.

First, the logical link control and adaptation protocol (L2CAP) 41 mayprovide one bidirectional channel for transmitting data to a specificprotocol or profile.

The L2CAP 41 may be operable to multiplex data between higher layerprotocols, segment and reassemble packages, and manage multicast datatransmission.

In Bluetooth LE, three fixed channels (one for signaling CH, one forsecurity manager, and one for attribute protocol) are basically used.Also, a dynamic channel may be used as needed.

Meanwhile, a basic channel/enhanced data rate (BR/EDR) uses a dynamicchannel and supports protocol service multiplexer, retransmission,streaming mode, and the like.

The security manager (SM) 42 is a protocol for authenticating devicesand providing key distribution.

The attribute protocol (ATT) 43 defines a rule for accessing data of acounterpart device in a server-client structure. The ATT has thefollowing 6 message types (request, response, command, notification,indication, confirmation).

{circle around (1)} Request and Response message: A request message is amessage for requesting specific information from the client device tothe server device, and the response message is a response message to therequest message, which is a message transmitted from the server deviceto the client device.

{circle around (2)} Command message: It is a message transmitted fromthe client device to the server device in order to indicate a command ofa specific operation. The server device does not transmit a responsewith respect to the command message to the client device.

{circle around (3)} Notification message: It is a message transmittedfrom the server device to the client device in order to notify an event,or the like. The client device does not transmit a confirmation messagewith respect to the notification message to the server device.

{circle around (4)} Indication and confirmation message: It is a messagetransmitted from the server device to the client device in order tonotify an event, or the like. Unlike the notification message, theclient device transmits a confirmation message regarding the indicationmessage to the server device.

In the present disclosure, when the GATT profile using the attributeprotocol (ATT) 43 requests long data, a value regarding a data length istransmitted to allow a client to clearly know the data length, and acharacteristic value may be received from a server by using a universalunique identifier (UUID).

The generic access profile (GAP) 45, a layer newly implemented for theBluetooth LE technology, is used to select a role for communicationbetween Bluetooth LED devices and to control how a multi-profileoperation takes place.

Also, the generic access profile (GAP) 45 is mainly used for devicediscovery, connection generation, and security procedure part, defines ascheme for providing information to a user, and defines types ofattributes as follows.

{circle around (1)} Service: It defines a basic operation of a device bya combination of behaviors related to data

{circle around (2)} Include: It defines a relationship between services

{circle around (3)} Characteristics: It is a data value used in a server

{circle around (4)} Behavior: It is a format that may be read by acomputer defined by a UUID (value type).

The LE profile 46, including profiles dependent upon the GATT, is mainlyapplied to a Bluetooth LE device. The LE profile 46 may include, forexample, Battery, Time, FindMe, Proximity, Time, Object DeliveryService, and the like, and details of the GATT-based profiles are asfollows.

{circle around (1)} Battery: Battery information exchanging method

{circle around (2)} Time: Time information exchanging method

{circle around (3)} FindMe: Provision of alarm service according todistance

{circle around (4)} Proximity: Battery information exchanging method

The generic attribute profile (GATT) 44 may operate as a protocoldescribing how the attribute protocol (ATT) 43 is used when services areconfigured. For example, the GATT 44 may operate to define how ATTattributes are grouped together with services and operate to describefeatures associated with services.

Thus, the GATT 44 and the ATT 43 may use features in order to describestatus and services of a device and describe how the features arerelated and used.

The wireless power transmission apparatus and the wireless powerreception apparatus according to the present disclosure may perform theroles of a client and a server, respectively. In an example, thewireless power transmission apparatus may be the client, and thewireless power reception apparatus may be the server. In anotherexample, the wireless power transmission apparatus may be the server,and the wireless power reception apparatus may be the client.

In addition, the wireless power transmission apparatus and the wirelesspower reception apparatus according to the present disclosure mayperform the roles of a scanner and an advertiser, respectively. In anexample, the wireless power transmission apparatus may be theadvertiser, and the wireless power reception apparatus may be thescanner. In another example, the wireless power transmission apparatusmay be the scanner, and the wireless power reception apparatus may bethe advertiser.

Hereinafter, procedures of the Bluetooth low energy (BLE) technologywill be briefly described.

The BLE procedure may be classified as a device filtering procedure, anadvertising procedure, a scanning procedure, a discovering procedure,and a connecting procedure.

Device Filtering Procedure

The device filtering procedure is a method for reducing the number ofdevices performing a response with respect to a request, indication,notification, and the like, in the controller stack.

When requests are received from all the devices, it is not necessary torespond thereto, and thus, the controller stack may perform control toreduce the number of transmitted requests to reduce power consumption.

An advertising device or scanning device may perform the devicefiltering procedure to limit devices for receiving an advertisingpacket, a scan request or a connection request.

Here, the advertising device refers to a device transmitting anadvertising event, that is, a device performing an advertisement and isalso termed an advertiser.

The scanning device refers to a device performing scanning, that is, adevice transmitting a scan request.

In the BLE, in a case in which the scanning device receives someadvertising packets from the advertising device, the scanning deviceshould transmit a scan request to the advertising device.

However, in a case in which a device filtering procedure is used so ascan request transmission is not required, the scanning device maydisregard the advertising packets transmitted from the advertisingdevice.

Even in a connection request process, the device filtering procedure maybe used. In a case in which device filtering is used in the connectionrequest process, it is not necessary to transmit a response with respectto the connection request by disregarding the connection request.

Advertising Procedure

The advertising device performs an advertising procedure to performundirected broadcast to devices within a region.

Here, the undirected broadcast is advertising toward all the devices,rather than broadcast toward a specific device, and all the devices mayscan advertising to make an supplemental information request or aconnection request.

In contrast, directed advertising may make an supplemental informationrequest or a connection request by scanning advertising for only adevice designated as a reception device.

The advertising procedure is used to establish a Bluetooth connectionwith an initiating device nearby.

Or, the advertising procedure may be used to provide periodicalbroadcast of user data to scanning devices performing listening in anadvertising channel.

In the advertising procedure, all the advertisements (or advertisingevents) are broadcast through an advertisement physical channel.

The advertising devices may receive scan requests from listening devicesperforming listening to obtain additional user data from advertisingdevices. The advertising devices transmit responses with respect to thescan requests to the devices which have transmitted the scan requests,through the same advertising physical channels as the advertisingphysical channels in which the scan requests have been received.

Broadcast user data sent as part of advertising packets are dynamicdata, while the scan response data is generally static data.

The advertisement device may receive a connection request from aninitiating device on an advertising (broadcast) physical channel. If theadvertising device has used a connectable advertising event and theinitiating device has not been filtered according to the devicefiltering procedure, the advertising device may stop advertising andenter a connected mode. The advertising device may start advertisingafter the connected mode.

Scanning Procedure

A device performing scanning, that is, a scanning device performs ascanning procedure to listen to undirected broadcasting of user datafrom advertising devices using an advertising physical channel.

The scanning device transmits a scan request to an advertising devicethrough an advertising physical channel in order to request additionaldata from the advertising device. The advertising device transmits ascan response as a response with respect to the scan request, byincluding additional user data which has requested by the scanningdevice through an advertising physical channel.

The scanning procedure may be used while being connected to other BLEdevice in the BLE piconet.

If the scanning device is in an initiator mode in which the scanningdevice may receive an advertising event and initiates a connectionrequest. The scanning device may transmit a connection request to theadvertising device through the advertising physical channel to start aBluetooth connection with the advertising device.

When the scanning device transmits a connection request to theadvertising device, the scanning device stops the initiator modescanning for additional broadcast and enters the connected mode.

Discovering Procedure

Devices available for Bluetooth communication (hereinafter, referred toas “Bluetooth devices”) perform an advertising procedure and a scanningprocedure in order to discover devices located nearby or in order to bediscovered by other devices within a given area.

The discovering procedure is performed asymmetrically. A Bluetoothdevice intending to discover other device nearby is termed a discoveringdevice, and listens to discover devices advertising an advertising eventthat may be scanned. A Bluetooth device which may be discovered by otherdevice and available to be used is termed a discoverable device andpositively broadcasts an advertising event such that it may be scannedby other device through an advertising (broadcast) physical channel.

Both the discovering device and the discoverable device may have alreadybeen connected with other Bluetooth devices in a piconet.

Connecting Procedure

A connecting procedure is asymmetrical, and requests that, while aspecific Bluetooth device is performing an advertising procedure,another Bluetooth device should perform a scanning procedure.

That is, an advertising procedure may be aimed, and as a result, onlyone device may response to the advertising. After a connectableadvertising event is received from an advertising device, a connectingrequest may be transmitted to the advertising device through anadvertising (broadcast) physical channel to initiate connection.

Hereinafter, operational states, that is, an advertising state, ascanning state, an initiating state, and a connection state, in the BLEtechnology will be briefly described.

Advertising State

A link layer (LL) enters an advertising state according to aninstruction from a host (stack). In a case in which the LL is in theadvertising state, the LL transmits an advertising packet data unit(PDU) in advertising events.

Each of the advertising events include at least one advertising PDU, andthe advertising PDU is transmitted through an advertising channel indexin use. After the advertising PDU is transmitted through an advertisingchannel index in use, the advertising event may be terminated, or in acase in which the advertising device may need to secure a space forperforming other function, the advertising event may be terminatedearlier.

Scanning State

The LL enters the scanning state according to an instruction from thehost (stack). In the scanning state, the LL listens to advertisingchannel indices.

The scanning state includes two types: passive scanning and activescanning. Each of the scanning types is determined by the host.

Time for performing scanning or an advertising channel index are notdefined.

During the scanning state, the LL listens to an advertising channelindex in a scan window duration. A scan interval is defined as aninterval between start points of two continuous scan windows.

When there is no collision in scheduling, the LL should listen in orderto complete all the scan intervals of the scan window as instructed bythe host. In each scan window, the LL should scan other advertisingchannel index. The LL uses every available advertising channel index.

In the passive scanning, the LL only receives packets and cannottransmit any packet.

In the active scanning, the LL performs listening in order to be reliedon an advertising PDU type for requesting advertising PDUs andadvertising device-related supplemental information from the advertisingdevice.

Initiating State

The LL enters the initiating state according to an instruction from thehost (stack).

When the LL is in the initiating state, the LL performs listening onadvertising channel indices.

During the initiating state, the LL listens to an advertising channelindex during the scan window interval.

Connection State

When the device performing a connection state, that is, when theinitiating device transmits a CONNECT_REQ PDU to the advertising deviceor when the advertising device receives a CONNECT_REQ PDU from theinitiating device, the LL enters a connection state.

It is considered that a connection is generated after the LL enters theconnection state. However, it is not necessary to consider that theconnection should be established at a point in time at which the LLenters the connection state. The only difference between a newlygenerated connection and an already established connection is a LLconnection supervision timeout value.

When two devices are connected, the two devices play different roles.

An LL serving as a master is termed a master, and an LL serving as aslave is termed a slave. The master adjusts a timing of a connectingevent, and the connecting event refers to a point in time at which themaster and the slave are synchronized.

Hereinafter, packets defined in an Bluetooth interface will be brieflydescribed. BLE devices use packets defined as follows.

Packet Format

The LL has only one packet format used for both an advertising channelpacket and a data channel packet.

Each packet includes four fields of a preamble, an access address, aPDU, and a CRC.

When one packet is transmitted in an advertising physical channel, thePDU may be an advertising channel PDU, and when one packet istransmitted in a data physical channel, the PDU may be a data channelPDU.

Advertising Channel PDU

An advertising channel PDU has a 16-bit header and payload havingvarious sizes.

A PDU type field of the advertising channel PDU included in the heaterindicates PDU types defined in Table 3 below.

TABLE 3 PDU Type Packet Name 0000 ADV_IND 0001 ADV_DIRECT_IND 0010ADV_NONCONN_IND 0011 SCAN_REQ 0100 SCAN_RSP 0101 CONNECT_REQ 0110ADV_SCAN_IND 0111-1111 Reserved

Advertising PDU The following advertising channel PDU types are termedadvertising PDUs and used in a specific event.

ADV_IND: Connectable undirected advertising event ADV_DIRECT_IND:Connectable directed advertising event

ADV_DIRECT_IND: Connectable directed advertising event

ADV_NONCONN_IND: Unconnectable undirected advertising event

ADV_SCAN_IND: Scannable undirected advertising event

The PDUs are transmitted from the LL in an advertising state, andreceived by the LL in a scanning state or in an initiating state.

Scanning PDU

The following advertising channel DPU types are termed scanning PDUs andare used in a state described hereinafter.

SCAN_REQ: Transmitted by the LL in a scanning state and received by theLL in an advertising state.

SCAN_RSP: Transmitted by the LL in the advertising state and received bythe LL in the scanning state.

Initiating PDU

The following advertising channel PDU type is termed an initiating PDU.

CONNECT_REQ: Transmitted by the LL in the initiating state and receivedby the LL in the advertising state.

Data Channel PDU

The data channel PDU may include a message integrity check (MIC) fieldhaving a 16-bit header and payload having various sizes.

The procedures, states, and packet formats in the BLE technologydiscussed above may be applied to perform the methods proposed in thepresent disclosure.

Referring to FIG. 4 a, The load (455) may correspond to a battery. Thebattery may store energy by using the power that is being outputted fromthe power pick-up circuit (210). Meanwhile, the battery is notmandatorily required to be included in the mobile device (450). Forexample, the battery may be provided as a detachable external feature.As another example, the wireless power receiver may include an operatingmeans that may execute diverse functions of the electronic deviceinstead of the battery.

As shown in the drawing, although the mobile device (450) is illustratedto be included in the wireless power receiver (200) and the base station(400) is illustrated to be included in the wireless power transmitter(100), in a broader meaning, the wireless power receiver (200) may beidentified (or regarded) as the mobile device (450), and the wirelesspower transmitter (100) may be identified (or regarded) as the basestation (400).

When the communication/control circuit 120 and the communication/controlcircuit 220 include Bluetooth or Bluetooth LE as an OB communicationmodule or a short-range communication module in addition to the IBcommunication module, the wireless power transmitter 100 including thecommunication/control circuit 120 and the wireless power receiver 200including the communication/control circuit 220 may be represented by asimplified block diagram as shown in FIG. 4 c.

FIG. 4c is a block diagram illustrating a wireless power transfer systemusing BLE communication according to an example.

Referring to FIG. 4 c, the wireless power transmitter 100 includes apower conversion circuit 110 and a communication/control circuit 120.The communication/control circuit 120 includes an in-band communicationmodule 121 and a BLE communication module 122.

Meanwhile, the wireless power receiver 200 includes a power pickupcircuit 210 and a communication/control circuit 220. Thecommunication/control circuit 220 includes an in-band communicationmodule 221 and a BLE communication module 222.

In one aspect, the BLE communication modules 122 and 222 perform thearchitecture and operation according to FIG. 4 b. For example, the BLEcommunication modules 122 and 222 may be used to establish a connectionbetween the wireless power transmitter 100 and the wireless powerreceiver 200 and exchange control information and packets necessary forwireless power transfer.

In another aspect, the communication/control circuit 120 may beconfigured to operate a profile for wireless charging. Here, the profilefor wireless charging may be GATT using BLE transmission.

Referring to FIG. 4 d, the communication/control circuits 120 and 220respectively include only in-band communication modules 121 and 221, andthe BLE communication modules 122 and 222 may be provided to beseparated from the communication/control circuits 120 and 220.

Hereinafter, the coil or coil unit includes a coil and at least onedevice being approximate to the coil, and the coil or coil unit may alsobe referred to as a coil assembly, a coil cell, or a cell.

FIG. 5 is a state transition diagram for describing a wireless powertransfer procedure.

Referring to FIG. 5, the power transfer (or transfer) from the wirelesspower transmitter to the wireless power receiver according to anexemplary embodiment of the present disclosure may be broadly dividedinto a selection phase (510), a ping phase (520), an identification andconfiguration phase (530), a negotiation phase (540), a calibrationphase (550), a power transfer phase (560), and a renegotiation phase(570).

If a specific error or a specific event is detected when the powertransfer is initiated or while maintaining the power transfer, theselection phase (510) may include a shifting phase (or step)—referencenumerals S502, S504, S508, S510, and S512. Herein, the specific error orspecific event will be specified in the following description.Additionally, during the selection phase (510), the wireless powertransmitter may monitor whether or not an object exists on an interfacesurface. If the wireless power transmitter detects that an object isplaced on the interface surface, the process step may be shifted to theping phase (520). During the selection phase (510), the wireless powertransmitter may transmit an analog ping having a power signal(or apulse) corresponding to an extremely short duration, and may detectwhether or not an object exists within an active area of the interfacesurface based on a current change in the transmitting coil or theprimary coil.

In case an object is sensed (or detected) in the selection phase (510),the wireless power transmitter may measure a quality factor of awireless power resonance circuit (e.g., power transfer coil and/orresonance capacitor). According to the exemplary embodiment of thepresent disclosure, during the selection phase (510), the wireless powertransmitter may measure the quality factor in order to determine whetheror not a foreign object exists in the charging area along with thewireless power receiver. In the coil that is provided in the wirelesspower transmitter, inductance and/or components of the series resistancemay be reduced due to a change in the environment, and, due to suchdecrease, a value of the quality factor may also be decreased. In orderto determine the presence or absence of a foreign object by using themeasured quality factor value, the wireless power transmitter mayreceive from the wireless power receiver a reference quality factorvalue, which is measured in advance in a state where no foreign objectis placed within the charging area. The wireless power transmitter maydetermine the presence or absence of a foreign object by comparing themeasured quality factor value with the reference quality factor value,which is received during the negotiation phase (540). However, in caseof a wireless power receiver having a low reference quality factorvalue—e.g., depending upon its type, purpose, characteristics, and soon, the wireless power receiver may have a low reference quality factorvalue—in case a foreign object exists, since the difference between thereference quality factor value and the measured quality factor value issmall (or insignificant), a problem may occur in that the presence ofthe foreign object cannot be easily determined. Accordingly, in thiscase, other determination factors should be further considered, or thepresent or absence of a foreign object should be determined by usinganother method.

According to another exemplary embodiment of the present disclosure, incase an object is sensed (or detected) in the selection phase (510), inorder to determine whether or not a foreign object exists in thecharging area along with the wireless power receiver, the wireless powertransmitter may measure the quality factor value within a specificfrequency area (e.g., operation frequency area). In the coil that isprovided in the wireless power transmitter, inductance and/or componentsof the series resistance may be reduced due to a change in theenvironment, and, due to such decrease, the resonance frequency of thecoil of the wireless power transmitter may be changed (or shifted). Morespecifically, a quality factor peak frequency that corresponds to afrequency in which a maximum quality factor value is measured within theoperation frequency band may be moved (or shifted).

In the ping phase (520), if the wireless power transmitter detects thepresence of an object, the transmitter activates (or Wakes up) areceiver and transmits a digital ping for identifying whether or not thedetected object corresponds to the wireless power receiver. During theping phase (520), if the wireless power transmitter fails to receive aresponse signal for the digital ping—e.g., a signal intensitypacket—from the receiver, the process may be shifted back to theselection phase (510). Additionally, in the ping phase (520), if thewireless power transmitter receives a signal indicating the completionof the power transfer—e.g., charging complete packet—from the receiver,the process may be shifted back to the selection phase (510).

If the ping phase (520) is completed, the wireless power transmitter mayshift to the identification and configuration phase (530) foridentifying the receiver and for collecting configuration and statusinformation.

In the identification and configuration phase (530), if the wirelesspower transmitter receives an unwanted packet (i.e., unexpected packet),or if the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., out of time), or if a packettransmission error occurs (i.e., transmission error), or if a powertransfer contract is not configured (i.e., no power transfer contract),the wireless power transmitter may shift to the selection phase (510).

The wireless power transmitter may confirm (or verify) whether or notits entry to the negotiation phase (540) is needed based on aNegotiation field value of the configuration packet, which is receivedduring the identification and configuration phase (530). Based on theverified result, in case a negotiation is needed, the wireless powertransmitter enters the negotiation phase (540) and may then perform apredetermined FOD detection procedure. Conversely, in case a negotiationis not needed, the wireless power transmitter may immediately enter thepower transfer phase (560). In the case that the wireless powertransmission apparatus and the wireless power reception apparatussupport an out-band communication such as BLE, in the identification andconfiguration phase (530), the out-band communication module of thewireless power transmission apparatus receives an ID or identificationpacket of the wireless power reception apparatus and exchanges a messagerelated to a configuration required for a power transmission.

In the negotiation phase (540), the wireless power transmitter mayreceive a Foreign Object Detection (FOD) status packet that includes areference quality factor value. Or, the wireless power transmitter mayreceive an FOD status packet that includes a reference peak frequencyvalue. Alternatively, the wireless power transmitter may receive astatus packet that includes a reference quality factor value and areference peak frequency value. At this point, the wireless powertransmitter may determine a quality coefficient threshold value for FOdetection based on the reference quality factor value. The wirelesspower transmitter may determine a peak frequency threshold value for FOdetection based on the reference peak frequency value.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined quality coefficientthreshold value for FO detection and the currently measured qualityfactor value (i.e., the quality factor value that was measured beforethe ping phase), and, then, the wireless power transmitter may controlthe transmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present disclosure will not be limited only to this.

The wireless power transmitter may detect the presence or absence of anFO in the charging area by using the determined peak frequency thresholdvalue for FO detection and the currently measured peak frequency value(i.e., the peak frequency value that was measured before the pingphase), and, then, the wireless power transmitter may control thetransmitted power in accordance with the FO detection result. Forexample, in case the FO is detected, the power transfer may be stopped.However, the present disclosure will not be limited only to this.

In case the FO is detected, the wireless power transmitter may return tothe selection phase (510). Conversely, in case the FO is not detected,the wireless power transmitter may proceed to the calibration phase(550) and may, then, enter the power transfer phase (560). Morespecifically, in case the FO is not detected, the wireless powertransmitter may determine the intensity of the received power that isreceived by the receiving end during the calibration phase (550) and maymeasure power loss in the receiving end and the transmitting end inorder to determine the intensity of the power that is transmitted fromthe transmitting end. In other words, during the calibration phase(550), the wireless power transmitter may estimate the power loss basedon a difference between the transmitted power of the transmitting endand the received power of the receiving end. The wireless powertransmitter according to the exemplary embodiment of the presentdisclosure may calibrate the threshold value for the FOD detection byapplying the estimated power loss.

In the case that the wireless power transmission apparatus and thewireless power reception apparatus support an out-band communicationsuch as BLE, in the calibration phase (550), the in-band communicationmodules of the wireless power transmission apparatus and the wirelesspower reception apparatus may exchange information required in theforeign material detection algorithm according to the charge profile.

In addition, in the case that the wireless power transmission apparatusand the wireless power reception apparatus support an out-bandcommunication such as BLE, in the negotiation phase (540), a BLEcommunication may be used, which is connected for exchanging andnegotiating information related to a wireless power transmission.Furthermore, when an exchange of the information related to a wirelesspower transmission is completed through BLE during the negotiation phase(540), the out-band communication module may inform the in-bandcommunication module (or control circuit) of the completion of thewireless power transmission and may transfer a start power transfermessage that commands a start of a wireless power transmission to thein-band communication module (or control circuit).

In the power transfer phase (560), in case the wireless powertransmitter receives an unwanted packet (i.e., unexpected packet), or incase the wireless power transmitter fails to receive a packet during apredetermined period of time (i.e., time-out), or in case a violation ofa predetermined power transfer contract occurs (i.e., power transfercontract violation), or in case charging is completed, the wirelesspower transmitter may shift to the selection phase (510).

Additionally, in the power transfer phase (560), in case the wirelesspower transmitter is required to reconfigure the power transfer contractin accordance with a status change in the wireless power transmitter,the wireless power transmitter may shift to the renegotiation phase(570). At this point, if the renegotiation is successfully completed,the wireless power transmitter may return to the power transfer phase(560).

In this embodiment, the calibration step 550 and the power transferphase 560 are divided into separate steps, but the calibration step 550may be integrated into the power transfer phase 560. In this case,operations in the calibration step 550 may be performed in the powertransfer phase 560.

The above-described power transfer contract may be configured based onthe status and characteristic information of the wireless powertransmitter and receiver. For example, the wireless power transmitterstatus information may include information on a maximum amount oftransmittable power, information on a maximum number of receivers thatmay be accommodated, and so on. And, the receiver status information mayinclude information on the required power, and so on.

FIG. 6 shows a power control method according to an exemplary embodimentof the present disclosure.

As shown in FIG. 6, in the power transfer phase (560), by alternatingthe power transfer and/or reception and communication, the wirelesspower transmitter (100) and the wireless power receiver (200) maycontrol the amount (or size) of the power that is being transferred. Thewireless power transmitter and the wireless power receiver operate at aspecific control point. The control point indicates a combination of thevoltage and the electric current that are provided from the output ofthe wireless power receiver, when the power transfer is performed.

More specifically, the wireless power receiver selects a desired controlpoint, a desired output current/voltage, a temperature at a specificlocation of the mobile device, and so on, and additionally determines anactual control point at which the receiver is currently operating. Thewireless power receiver calculates a control error value by using thedesired control point and the actual control point, and, then, thewireless power receiver may transmit the calculated control error valueto the wireless power transmitter as a control error packet.

Also, the wireless power transmitter may configure/control a newoperating point—amplitude, frequency, and duty cycle—by using thereceived control error packet, so as to control the power transfer.Therefore, the control error packet may be transmitted/received at aconstant time interval during the power transfer phase, and, accordingto the exemplary embodiment, in case the wireless power receiverattempts to reduce the electric current of the wireless powertransmitter, the wireless power receiver may transmit the control errorpacket by setting the control error value to a negative number. And, incase the wireless power receiver intends to increase the electriccurrent of the wireless power transmitter, the wireless power receivertransmit the control error packet by setting the control error value toa positive number. During the induction mode, by transmitting thecontrol error packet to the wireless power transmitter as describedabove, the wireless power receiver may control the power transfer.

In the resonance mode, which will hereinafter be described in detail,the device may be operated by using a method that is different from theinduction mode. In the resonance mode, one wireless power transmittershould be capable of serving a plurality of wireless power receivers atthe same time. However, in case of controlling the power transfer justas in the induction mode, since the power that is being transferred iscontrolled by a communication that is established with one wirelesspower receiver, it may be difficult to control the power transfer ofadditional wireless power receivers. Therefore, in the resonance modeaccording to the present disclosure, a method of controlling the amountof power that is being received by having the wireless power transmittercommonly transfer (or transmit) the basic power and by having thewireless power receiver control its own resonance frequency.Nevertheless, even during the operation of the resonance mode, themethod described above in FIG. 6 will not be completely excluded. And,additional control of the transmitted power may be performed by usingthe method of FIG. 6.

FIG. 7 is a block diagram of a wireless power transmitter according toanother exemplary embodiment of the present disclosure. This may belongto a wireless power transfer system that is being operated in themagnetic resonance mode or the shared mode. The shared mode may refer toa mode performing a several-for-one (or one-to-many) communication andcharging between the wireless power transmitter and the wireless powerreceiver. The shared mode may be implemented as a magnetic inductionmethod or a resonance method.

Referring to FIG. 7, the wireless power transmitter (700) may include atleast one of a cover (720) covering a coil assembly, a power adapter(730) supplying power to the power transmitter (740), a powertransmitter (740) transmitting wireless power, and a user interface(750) providing information related to power transfer processing andother related information. Most particularly, the user interface (750)may be optionally included or may be included as another user interface(750) of the wireless power transmitter (700).

The power transmitter (740) may include at least one of a coil assembly(760), an impedance matching circuit (770), an inverter (780), acommunication circuit (790), and a control circuit (710).

The coil assembly (760) includes at least one primary coil generating amagnetic field. And, the coil assembly (760) may also be referred to asa coil cell. The coil assembly 760 may be called a transmitter sideresonator (Tx resonator).

The impedance matching circuit (770) may provide impedance matchingbetween the inverter and the primary coil(s). The impedance matchingcircuit (770) may generate resonance from a suitable frequency thatboosts the electric current of the primary coil(s). In a multi-coilpower transmitter (740), the impedance matching circuit may additionallyinclude a multiplex that routes signals from the inverter to a subset ofthe primary coils. The impedance matching circuit may also be referredto as a tank circuit.

The impedance matching circuit (770) may include a capacitor, aninductor, and a switching device that switches the connection betweenthe capacitor and the inductor. The impedance matching may be performedby detecting a reflective wave of the wireless power that is beingtransferred (or transmitted) through the coil assembly (760) and byswitching the switching device based on the detected reflective wave,thereby adjusting the connection status of the capacitor or the inductoror adjusting the capacitance of the capacitor or adjusting theinductance of the inductor. In some cases, the impedance matching may becarried out even though the impedance matching circuit (770) is omitted.This specification also includes an exemplary embodiment of the wirelesspower transmitter (700), wherein the impedance matching circuit (770) isomitted.

For example, the impedance matching circuit 770 may include a total offour inverters for power conversion per coil and receive a PWM signalfrom the control circuit 710. The impedance matching circuit 770 isdriven by transmitting a signal to the inverter through two 4-channellogic switches.

The inverter (780) may convert a DC input to an AC signal. The inverter(780) may be operated as a half-bridge inverter or a full-bridgeinverter in order to generate a pulse wave and a duty cycle of anadjustable frequency. Additionally, the inverter may include a pluralityof stages in order to adjust input voltage levels.

The communication circuit (790) may perform communication with the powerreceiver. The power receiver performs load modulation in order tocommunicate requests and information corresponding to the powertransmitter. Therefore, the power transmitter (740) may use thecommunication circuit (790) so as to monitor the amplitude and/or phaseof the electric current and/or voltage of the primary coil in order todemodulate the data being transmitted from the power receiver. Thecommunication circuit (790) may include both of the in-bandcommunication module and the out-band communication module or either oneof the in-band communication module or the out-band communicationmodule. The communication circuit 790 is configured to search thewireless power reception apparatus 800 or transmit data to the wirelesspower reception apparatus 800. Here, the communication circuit 790 maybe configured to perform a process related to an authentication of thewireless power reception apparatus 800. Here, the authentication mayinclude a Qi authentication. For example, the communication circuit 790may receive information related to the authentication from the wirelesspower reception apparatus 800 or transmit the information related to theauthentication to the wireless power reception apparatus 800.

Additionally, the power transmitter (740) may control the output powerto that the data may be transferred through the communication circuit(790) by using a Frequency Shift Keying (FSK) method, and so on.

The control circuit (710) may control communication and power transfer(or delivery) of the power transmitter (740). The control circuit (710)may control the power transfer by adjusting the above-describedoperating point. The operating point may be determined by, for example,at least any one of the operation frequency, the duty cycle, and theinput voltage. The control circuit 710 may be configured to perform aprocess related to an authentication of the wireless power receptionapparatus 800. Here, the authentication may include a Qi authentication.

The communication circuit (790) and the control circuit (710) may eachbe provided as a separate circuit/device/chipset or may be collectivelyprovided as one circuit/device/chipset.

FIG. 8 shows a wireless power receiver according to another exemplaryembodiment of the present disclosure. This may belong to a wirelesspower transfer system that is being operated in the magnetic resonancemode or the shared mode.

Referring to FIG. 8, the wireless power receiver (800) may include atleast one of a user interface (820) providing information related topower transfer processing and other related information, a powerreceiver (830) receiving wireless power, a load circuit (840), and abase (850) supporting and covering the coil assembly. Most particularly,the user interface (820) may be optionally included or may be includedas another user interface (820) of the wireless power receiver (800).

The power receiver (830) may include at least one of a power converter(860), an impedance matching circuit (870), a coil assembly (880), acommunication circuit (890), and a control circuit (810).

The power converter (860) may convert the AC power that is received fromthe secondary coil to a voltage and electric current that are suitablefor the load circuit. According to an exemplary embodiment, the powerconverter (860) may include a rectifier. The rectifier may rectify thereceived wireless power and may convert the power from an alternatingcurrent (AC) to a direct current (DC). The rectifier may convert thealternating current to the direct current by using a diode or atransistor, and, then, the rectifier may smooth the converted current byusing the capacitor and resistance. Herein, a full-wave rectifier, ahalf-wave rectifier, a voltage multiplier, and so on, that areimplemented as a bridge circuit may be used as the rectifier.Additionally, the power converter may adapt a reflected impedance of thepower receiver.

The impedance matching circuit (870) may provide impedance matchingbetween a combination of the power converter (860) and the load circuit(840) and the secondary coil. According to an exemplary embodiment, theimpedance matching circuit may generate a resonance of approximately 100kHz, which may reinforce the power transfer. The impedance matchingcircuit (870) may include a capacitor, an inductor, and a switchingdevice that switches the combination of the capacitor and the inductor.The impedance matching may be performed by controlling the switchingdevice of the circuit that configured the impedance matching circuit(870) based on the voltage value, electric current value, power value,frequency value, and so on, of the wireless power that is beingreceived. Alternatively, the impedance matching circuit 870 may includea total of four inverters for power conversion per coil and receive aPWM signal from the control circuit 810. The impedance matching circuit870 is driven by transmitting a signal to the inverter through two4-channel logic switches.

In some cases, the impedance matching may be carried out even though theimpedance matching circuit (870) is omitted. This specification alsoincludes an exemplary embodiment of the wireless power receiver (200),wherein the impedance matching circuit (870) is omitted.

The coil assembly (880) includes at least one secondary coil, and,optionally, the coil assembly (880) may further include an elementshielding the metallic part of the receiver from the magnetic field. Thecoil assembly 880 may be called a receiver side resonator (Rxresonator).

The communication circuit (890) may perform load modulation in order tocommunicate requests and other information to the power transmitter. Forthis, the power receiver (830) may perform switching of the resistanceor capacitor so as to change the reflected impedance.

The communication circuit 890 may include both of the in-bandcommunication module and the out-band communication module or either oneof the in-band communication module or the out-band communicationmodule. The communication circuit 890 is configured to search thewireless power transmission apparatus 700 or transmit data to thewireless power transmission apparatus 700. Here, the communicationcircuit 890 may be configured to perform a process related to anauthentication of the wireless power transmission apparatus 700. Here,the authentication may include a Qi authentication. For example, thecommunication circuit 890 may receive information related to theauthentication from the wireless power transmission apparatus 700 ortransmit the information related to the authentication to the wirelesspower transmission apparatus 700.

The control circuit (810) may control the received power. For this, thecontrol circuit (810) may determine/calculate a difference between anactual operating point and a target operating point of the powerreceiver (830). Thereafter, by performing a request for adjusting thereflected impedance of the power transmitter and/or for adjusting anoperating point of the power transmitter, the difference between theactual operating point and the target operating point may beadjusted/reduced. In case of minimizing this difference, an optimalpower reception may be performed. The control circuit 710 may beconfigured to perform a process related to an authentication of thewireless power transmission apparatus 700. Here, the authentication mayinclude a Qi authentication.

The communication circuit (890) and the control circuit (810) may eachbe provided as a separate device/chipset or may be collectively providedas one device/chipset.

FIG. 9 shows a communication frame structure according to an exemplaryembodiment of the present disclosure. This may correspond to acommunication frame structure in a shared mode.

Referring to FIG. 9, in the shared mode, different forms of frames maybe used along with one another. For example, in the shared mode, aslotted frame having a plurality of slots, as shown in (A), and a freeformat frame that does not have a specified format, as shown in (B), maybe used. More specifically, the slotted frame corresponds to a frame fortransmitting short data packets from the wireless power receiver (200)to the wireless power transmitter (100). And, since the free formatframe is not configured of a plurality of slots, the free format framemay correspond to a frame that is capable of performing transmission oflong data packets.

Meanwhile, the slotted frame and the free format frame may be referredto other diverse terms by anyone skilled in the art. For example, theslotted frame may be alternatively referred to as a channel frame, andthe free format frame may be alternatively referred to as a messageframe.

More specifically, the slotted frame may include a sync patternindicating the starting point (or beginning) of a slot, a measurementslot, nine slots, and additional sync patterns each having the same timeinterval that precedes each of the nine slots.

Herein, the additional sync pattern corresponds to a sync pattern thatis different from the sync pattern that indicates the starting point ofthe above-described frame. More specifically, the additional syncpattern does not indicate the starting point of the frame but mayindicate information related to the neighboring (or adjacent) slots(i.e., two consecutive slots positioned on both sides of the syncpattern).

Among the nine slots, each sync pattern may be positioned between twoconsecutive slots. In this case, the sync pattern may provideinformation related to the two consecutive slots.

Additionally, the nine slots and the sync patterns being provided beforeeach of the nine slots may have the same time interval. For example, thenine slots may have a time interval of 50 ms. And, the nine syncpatterns may have a time length of 50 ms.

Meanwhile, the free format frame, as shown in (B) may not have aspecific format apart from the sync pattern indicating the startingpoint of the frame and the measurement slot. More specifically, the freeformat frame is configured to perform a function that is different fromthat of the slotted frame. For example, the free format frame may beused to perform a function of performing communication of long datapackets (e.g., additional owner information packets) between thewireless power transmitter and the wireless power receiver, or, in caseof a wireless power transmitter being configured of multiple coils, toperform a function of selecting any one of the coils.

Hereinafter, a sync pattern that is included in each frame will bedescribed in more detail with reference to the accompanying drawings.

FIG. 10 is a structure of a sync pattern according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 10, the sync pattern may be configured of a preamble,a start bit, a response field, a type field, an info field, and a paritybit. In FIG. 10, the start bit is illustrated as ZERO.

More specifically, the preamble is configured of consecutive bits, andall of the bits may be set to 0. In other words, the preamble maycorrespond to bits for matching a time length of the sync pattern.

The number of bits configuring the preamble may be subordinate to theoperation frequency so that the length of the sync pattern may be mostapproximate to 50 ms but within a range that does not exceed 50 ms. Forexample, in case the operation frequency corresponds to 100 kHz, thesync pattern may be configured of two preamble bits, and, in case theoperation frequency corresponds to 105 kHz, the sync pattern may beconfigured of three preamble bits.

The start bit may correspond to a bit that follows the preamble, and thestart bit may indicate ZERO. The ZERO may correspond to a bit thatindicates a type of the sync pattern. Herein, the type of sync patternsmay include a frame sync including information that is related to aframe, and a slot sync including information of the slot. Morespecifically, the sync pattern may be positioned between consecutiveframes and may correspond to a frame sync that indicate a start of theframe, or the sync pattern may be positioned between consecutive slotsamong a plurality of slots configuring the frame and may correspond to async slot including information related to the consecutive slots.

For example, in case the ZERO is equal to 0, this may indicate that thecorresponding slot is a slot sync that is positioned in-between slots.And, in case the ZERO is equal to 1, this may indicate that thecorresponding sync pattern is a frame sync being located in-betweenframes.

A parity bit corresponds to a last bit of the sync pattern, and theparity bit may indicate information on a number of bits configuring thedata fields (i.e., the response field, the type field, and the infofield) that are included in the sync pattern. For example, in case thenumber of bits configuring the data fields of the sync patterncorresponds to an even number, the parity bit may be set to when, and,otherwise (i.e., in case the number of bits corresponds to an oddnumber), the parity bit may be set to 0.

The response field may include response information of the wirelesspower transmitter for its communication with the wireless power receiverwithin a slot prior to the sync pattern. For example, in case acommunication between the wireless power transmitter and the wirelesspower receiver is not detected, the response field may have a value of‘00’. Additionally, if a communication error is detected in thecommunication between the wireless power transmitter and the wirelesspower receiver, the response field may have a value of ‘01’. Thecommunication error corresponds to a case where two or more wirelesspower receivers attempt to access one slot, thereby causing collision tooccur between the two or more wireless power receivers.

Additionally, the response field may include information indicatingwhether or not the data packet has been accurately received from thewireless power receiver. More specifically, in case the wireless powertransmitter has denied the data packet, the response field may have avalue of “10” (10—not acknowledge (NAK)). And, in case the wirelesspower transmitter has confirmed the data packet, the response field mayhave a value of “11” (11—acknowledge (ACK)).

The type field may indicate the type of the sync pattern. Morespecifically, in case the sync pattern corresponds to a first syncpattern of the frame (i.e., as the first sync pattern, in case the syncpattern is positioned before the measurement slot), the type field mayhave a value of ‘1’, which indicates a frame sync.

Additionally, in a slotted frame, in case the sync pattern does notcorrespond to the first sync pattern of the frame, the type field mayhave a value of ‘0’, which indicates a slot sync.

Moreover, the information field may determine the meaning of its valuein accordance with the sync pattern type, which is indicated in the typefield. For example, in case the type field is equal to 1 (i.e., in casethe sync pattern type indicates a frame sync), the meaning of theinformation field may indicate the frame type. More specifically, theinformation field may indicate whether the current frame corresponds toa slotted frame or a free-format frame. For example, in case theinformation field is given a value of ‘00’, this indicates that thecurrent frame corresponds to a slotted frame. And, in case theinformation field is given a value of ‘01’, this indicates that thecurrent frame corresponds to a free-format frame.

Conversely, in case the type field is equal to 0 (i.e., in case the syncpattern type indicates a slot sync), the information field may indicatea state of a next slot, which is positioned after the sync pattern. Morespecifically, in case the next slot corresponds to a slot that isallocated (or assigned) to a specific wireless power receiver, theinformation field is given a value of ‘00’. In case the next slotcorresponds to a slot that is locked, so as to be temporarily used bythe specific wireless power receiver, the information field is given avalue of ‘01’. Alternatively, in case the next slot corresponds to aslot that may be freely used by a random wireless power receiver, theinformation field is given a value of ‘10’.

FIG. 11 shows operation statuses of a wireless power transmitter and awireless power receiver in a shared mode according to an exemplaryembodiment of the present disclosure.

Referring to FIG. 11, the wireless power receiver operating in theshared mode may be operated in any one of a selection phase (1100), anintroduction phase (1110), a configuration phase (1120), a negotiationphase (1130), and a power transfer phase (1140).

Firstly, the wireless power transmitter according to the exemplaryembodiment of the present disclosure may transmit a wireless powersignal in order to detect the wireless power receiver. Morespecifically, a process of detecting a wireless power receiver by usingthe wireless power signal may be referred to as an Analog ping.

Meanwhile, the wireless power receiver that has received the wirelesspower signal may enter the selection phase (1100). As described above,the wireless power receiver that has entered the selection phase (1100)may detect the presence or absence of an FSK signal within the wirelesspower signal.

In other words, the wireless power receiver may perform communication byusing any one of an exclusive mode and a shared mode in accordance withthe presence or absence of the FSK signal.

More specifically, in case the FSK signal is included in the wirelesspower signal, the wireless power receiver may operate in the sharedmode, and, otherwise, the wireless power receiver may operate in theexclusive mode.

In case the wireless power receiver operates in the shared mode, thewireless power receiver may enter the introduction phase (1110). In theintroduction phase (1110), the wireless power receiver may transmit acontrol information (CI) packet to the wireless power transmitter inorder to transmit the control information packet during theconfiguration phase, the negotiation phase, and the power transferphase. The control information packet may have a header and informationrelated to control. For example, in the control information packet, theheader may correspond to 0X53.

In the introduction phase (1110), the wireless power receiver performsan attempt to request a free slot for transmitting the controlinformation (CI) packet during the following configuration phase,negotiation phase, and power transfer phase. At this point, the wirelesspower receiver selects a free slot and transmits an initial CI packet.If the wireless power transmitter transmits an ACK as a response to thecorresponding CI packet, the wireless power receiver enters theconfiguration phase. If the wireless power transmitter transmits a NACKas a response to the corresponding CI packet, this indicates thatanother wireless power receiver is performing communication through theconfiguration and negotiation phase. In this case, the wireless powerreceiver re-attempts to perform a request for a free slot.

If the wireless power receiver receives an ACK as a response to the CIpacket, the wireless power receiver may determine the position of aprivate slot within the frame by counting the remaining sync slots up tothe initial frame sync. In all of the subsequent slot-based frames, thewireless power receiver transmits the CI packet through thecorresponding slot.

If the wireless power transmitter authorizes the entry of the wirelesspower receiver to the configuration phase, the wireless powertransmitter provides a locked slot series for the exclusive usage of thewireless power receiver. This may ensure the wireless power receiver toproceed to the configuration phase without any collision.

The wireless power receiver transmits sequences of data packets, such astwo identification data packets (IDHI and IDLO), by using the lockedslots. When this phase is completed, the wireless power receiver entersthe negotiation phase. During the negotiation state, the wireless powertransmitter continues to provide the locked slots for the exclusiveusage of the wireless power receiver. This may ensure the wireless powerreceiver to proceed to the negotiation phase without any collision.

The wireless power receiver transmits one or more negotiation datapackets by using the corresponding locked slot, and the transmittednegotiation data packet(s) may be mixed with the private data packets.Eventually, the corresponding sequence is ended (or completed) alongwith a specific request (SRQ) packet. When the corresponding sequence iscompleted, the wireless power receiver enters the power transfer phase,and the wireless power transmitter stops the provision of the lockedslots.

In the power transfer phase, the wireless power receiver performs thetransmission of a CI packet by using the allocated slots and thenreceives the power. The wireless power receiver may include a regulatorcircuit. The regulator circuit may be included in acommunication/control circuit. The wireless power receiver mayself-regulate a reflected impedance of the wireless power receiverthrough the regulator circuit. In other words, the wireless powerreceiver may adjust the impedance that is being reflected for an amountof power that is requested by an external load. This may prevent anexcessive reception of power and overheating.

In the shared mode, (depending upon the operation mode) since thewireless power transmitter may not perform the adjustment of power as aresponse to the received CI packet, in this case, control may be neededin order to prevent an overvoltage state.

In the wireless power transmission system, in general, a communicationbetween a wireless power transmission apparatus and a wireless powerreception apparatus uses an amplitude shift keying (ASK) scheme using amagnetic field change and a frequency shift keying (FSK) scheme using afrequency change. However, a transmission speed according to ASK and FSKis limited to a few kHz, and since the ASK scheme and the FSK scheme arevulnerable to electronic and magnetic disturbances, the ASK scheme andthe FSK scheme are not suitable for a transmission of a large amount ofdata such as a middle-power level transmission required in an evolvedwireless power transmission system or an authentication.

Accordingly, in order to support various applications of a wirelesspower transmission, the wireless power transmission apparatus and thewireless power reception apparatus may use the out-band communication.For example, the out-band communication may include Bluetooth, BluetoothLow Energy (BLE), or NFC. In the present disclosure, the term out-bandcommunication is substantially the same as an out-of-band (OOB)communication but only different in the expression, and accordingly,hereinafter, the term out-band communication is used as a collectivemeaning. In addition, in the present disclosure, in an exemplary manner,the out-band communication is specified and described as BLE. However,in the embodiments described based on BLE, it is understood that theembodiments in which BLE is substituted by another out-bandcommunication also belong to the inventive concept of the presentdisclosure.

FIG. 12 illustrates a data expression, an operation form, and a systemarchitecture of BLE.

Referring to FIG. 12, in considering the data expression, the operationform, and the system architecture of BLE, a method for implementing aBLE reconnection process in a wireless power transmission system mayinclude various embodiments.

FIG. 13 is a flowchart illustrating a method for transmitting andreceiving a wireless power based on a BLE reconnection by the wirelesspower transmission apparatus and the wireless power reception apparatusaccording to an example.

Referring to FIG. 13, an in-band communication module and/or a controlunit of the wireless power reception apparatus PRx operates in a standbymode in which the wireless power transmission apparatus PTx may detectthe wireless power reception apparatus PRx, and an in-band communicationmodule and/or a control unit of the wireless power transmissionapparatus operates in an object detection mode (step S1300).

When the wireless power transmission apparatus and the wireless powerreception apparatus become close to each other, and in the case that thein-band communication module and/or the control unit of the wirelesspower transmission apparatus detects the wireless power receptionapparatus (step S1305), the in-band communication module and/or thecontrol unit of the wireless power transmission apparatus transmits ahandover message that commands to perform handover to an out-bandcommunication module of the wireless power transmission apparatus (stepS1310). In addition, the in-band communication module and/or the controlunit of the wireless power reception apparatus transmits a handovermessage that commands to perform handover to an out-band communicationmodule of the wireless power reception apparatus (step S1315).

When the out-band communication module of the wireless power receptionapparatus and the out-band communication module of the wireless powertransmission apparatus receive the handover message, the out-bandcommunication module of the wireless power reception apparatus and theout-band communication module of the wireless power transmissionapparatus perform a handover process in an out-band communication (stepS1320). Since an operation of establishing a BLE connection may beaccompanied by the handover process, for example, the handover processmay also be called a handover connection process.

When the handover to the out-band communication is completed, thesubsequent phases including the identification and configuration phaseprogress based on the out-band communication (step S1325). For example,the out-band communication module of the wireless power receptionapparatus and the out-band communication module of the wireless powertransmission apparatus may perform an exchange of information in theidentification and configuration phase, an exchange of information inthe negotiation phase, and an exchange of information in the calibrationphase. In the present disclosure, the information exchanged between thewireless power reception apparatus and the wireless power transmissionapparatus before the power transfer phase may be referred to as powercharacteristic information collectively. For example, in theidentification and configuration phase, the wireless power receptionapparatus transmits ID information and information related to aconfiguration required for a power transmission to the wireless powertransmission apparatus. For example, in the negotiation phase, thewireless power reception apparatus transmits information required for apower transmission such as information required for a foreign materialdetection algorithm and information for a communication environment tothe wireless power transmission apparatus. For example, in thecalibration phase, the information required for a foreign materialdetection algorithm according to a charge profile is exchanged betweenthe wireless power transmission apparatus and the wireless powerreception apparatus.

That is, before entering the power transfer phase, power characteristicinformation may be transmitted from the wireless power receptionapparatus to the wireless power transmission apparatus or transmittedfrom the wireless power transmission apparatus to the wireless powerreception apparatus based on the out-band communication.

In accordance with the phase progress of the out-band communicationmodule of the wireless power transmission apparatus and the out-bandcommunication module of the wireless power reception apparatus, thein-band communication module and the control unit of the wireless powertransmission apparatus and the in-band communication module and thecontrol unit of the wireless power reception apparatus also progress thephases.

When all the phases up to the calibration phase are completed based onthe out-band communication, the wireless power transmission apparatusand the wireless power reception apparatus enter the power transferphase, and the wireless power transmission apparatus transmits wirelesspower to the wireless power reception apparatus (step S1325).

When a situation in which the out-band communication is disconnectedwhile the wireless power is transmitted occurs (step S1340), thewireless power transmission apparatus and the wireless power receptionapparatus return to the initial step S1300 and may perform all theprocesses from step S1310 to step S1330 (step S1350). Owing to this, thetime consumed for a transmission of wireless power increases, thetransmission efficiency is degraded, and further, users may undergoconsiderable inconvenience in the case that the disconnection of theout-band communication occurs frequency. Accordingly, a method forsolving the problem by simplifying the reconnection process after theout-band communication is disconnected is in demand.

FIG. 14 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a BLE reconnection by the wirelesspower transmission apparatus and the wireless power reception apparatusaccording to another example.

Referring to FIG. 14, step S1400 to step S1430 are the same as theprocesses of step S1300 to step S1330 according to FIG. 13.

The wireless power transmission apparatus and the wireless powerreception apparatus perform a process of saving power state informationwhich is determined during the power transfer phase according to stepS1430 (step S1440). In this embodiment, the process of saving the powerstate information is a process of saving the power state information inadvance in preparation for the case when the out-band communication isdisconnected and then reconnected. This embodiment describes that theprocess of saving the power state information is performed afterentering the power transfer phase, but the process of saving the powerstate information may be performed before the out-band communication isinitially connected and enters the power transfer phase. The detailedembodiment of the process of saving the power state informationaccording to step S1440 is described below with reference to FIG. 15.

The power state information may include at least a part of informationexchanged or negotiated before entering the power transfer phase and/orinformation exchanged or negotiated after entering the power transferphase between the wireless power reception apparatus and the wirelesspower transmission apparatus. Alternatively, the power state informationmay be information defined as a power transfer contract between thewireless power reception apparatus and the wireless power transmissionapparatus. In an example, the power state information may includeinformation as represented in the following table.

TABLE 4 Field Octet Device ID 1 Device Address 6 Negotiated Power level1 Public key 16 Guaranteed Power 1 Maximum Power 1 Received Power PacketFormat 1 FSK Polarity/Modulation Depth 1 RFU . . .

Referring to Table 4, the power transfer information may include atleast one of device ID information of the wireless power receptionapparatus, device address information of the wireless power receptionapparatus, power level information, and a public key.

The device ID information indicates an ID for distinguishing devices. Anaddress of the device may indicate a Bluetooth MAC address, for example.The negotiated power level may indicate 5 W, 10 W, 15 W, 30 W, 60 W, andthe like, for example. The public key is a key used in Bluetooth paringand used in a secure connection based on ECDH. When both of the wirelesspower transmission apparatus and the wireless power reception apparatussupport the secure connection, P256 elliptic curve may be used. Wheneither one of the wireless power transmission apparatus or the wirelesspower reception apparatus supports the secure connection, P192 may beused. The guaranteed power has 1-byte size and may be defined as 5 W inthe Qi low power profile standard and may be defined as 15 W in theextended power profile (EPP) standard. The maximum power indicates amaximum power which may be allocated in the wireless power receptionapparatus for charging power. The received power packet may indicate anaverage value received by the wireless power reception apparatus fromthe wireless power transmission apparatus. The mode of the wirelesspower reception apparatus may be changed.

When a situation in which the out-band communication is disconnectedwhile wireless power is transmitted occurs (step S1450), the wirelesspower transmission apparatus and the wireless power reception apparatusreturn to the initial step S1400 and operate in the object detectionmode and the standby mode, respective (step S1400). Later, when thewireless power transmission apparatus detects the wireless powerreception apparatus (step S1460), the wireless power transmissionapparatus and the wireless power reception apparatus perform anautomatic reconnection process (step S1470). The automatic reconnectionprocess is a process required when performing a reconnection of theout-band communication again after the process of saving the power stateinformation. The detailed embodiment of the automatic reconnectionprocess is described below with reference to FIG. 16 to FIG. 18.

When a reconnection of the out-band communication is completed, thewireless power transmission apparatus and the wireless power receptionapparatus enter the power transfer phase directly and perform atransmission and reception of wireless power (step S1480).

FIG. 15 is a flowchart illustrating a method for transmitting andreceiving wireless power based on a process of saving the power stateinformation by the wireless power transmission apparatus and thewireless power reception apparatus according to an example.

Referring to FIG. 15, in the power transfer phase in which the wirelesspower transmission apparatus transmits a wireless power to the wirelesspower reception apparatus (step S1500), the process of saving the powerstate information is initiated (step S1440).

In the process of saving the power state information, the out-bandcommunication module of the wireless power transmission apparatustransmits a save request message to the out-band communication module ofthe wireless power reception apparatus (step S1510). In an example, thesave request message may include at least one of device ID information,device address information, power level information, and a public key.The save request message may also be called a power save requestmessage.

The out-band communication module of the wireless power receptionapparatus transmits an information save response message to the out-bandcommunication module of the wireless power transmission apparatus basedon the out-band communication (step S1520). The information saveresponse message may also be called a power information save responsemessage.

The out-band communication module of the wireless power receptionapparatus transmits a save information message to the in-bandcommunication module and/or the control circuit of the wireless powerreception apparatus, and the out-band communication module of thewireless power transmission apparatus transfers the save informationmessage to the in-band communication module and/or the control circuitof the wireless power transmission apparatus (step S1530). When theout-band communication is disconnected or disabled, the save informationmessage is transmitted for the purpose of using the power stateinformation in the in-band communication simultaneously. Later, theout-band communication is disconnected (step S1540), the reconnectionprocess of the out-band communication may be progressed.

FIG. 16 is a flowchart illustrating a method for transmitting andreceiving a wireless power based on a process of automatic reconnectionof the out-band communication by the wireless power transmissionapparatus and the wireless power reception apparatus according to anexample.

Referring to FIG. 16, while the state in which the out-bandcommunication between the out-band communication module of the wirelesspower transmission apparatus and the out-band communication module ofthe wireless power reception apparatus is maintained (step S1600), areconnection of the out-band communication is performed (step S1610).Here, since the existing devices which have been connected based on theout-band communication are registered in a whitelist, an automaticreconnection is available. When the reconnection of the out-bandcommunication is performed (step S1610), the out-band communicationmodule of the wireless power reception apparatus and the out-bandcommunication module of the wireless power transmission apparatusperform the automatic reconnection process (step S1470).

In describing step S1470 in more detail, the out-band communicationmodule of the wireless power transmission apparatus transmits aninformation request message to the out-band communication module of thewireless power reception apparatus to obtain the power state informationwhich is already saved in the wireless power reception apparatus (stepS1620). The information request message may also be called a powerinformation request message. Here, the information request message mayinclude at least one of device ID information, device addressinformation, power level information, and a public key.

Meanwhile, the out-band communication module of the wireless powerreception apparatus reads or generates the saved power state informationin response to the information request message, and then, transmits aninformation response message including the power state information tothe out-band communication module of the wireless power transmissionapparatus (step S1630). The information response message may include atleast one of device ID information, device address information, powerlevel information, and a public key. The information response messagemay also be called a power information response message.

Later, the wireless power transmission apparatus and the wireless powerreception apparatus enter the power transfer phase based on the powerstate information which is exchanged therebetween (step S1640).

FIG. 17 is a flowchart illustrating a method for transmitting andreceiving a wireless power based on a process of automatic reconnectionof the out-band communication by the wireless power transmissionapparatus and the wireless power reception apparatus according toanother example.

Referring to FIG. 17, while the state in which the out-bandcommunication between the out-band communication module of the wirelesspower transmission apparatus and the out-band communication module ofthe wireless power reception apparatus is maintained (step S1700), theout-band communication is reestablished (step S1710). Here, since theexisting devices which have been connected based on the out-bandcommunication are registered in a whitelist, an automatic reconnectionis available.

The out-band communication module of the wireless power receptionapparatus and the out-band communication module of the wireless powertransmission apparatus perform the automatic reconnection process (stepS1470).

In describing step S1470 in more detail, the out-band communicationmodule of the wireless power transmission apparatus transmits aninformation request message to the out-band communication module of thewireless power reception apparatus to obtain the power state informationwhich is already saved in the wireless power reception apparatus (stepS1720). The information request message may also be called a powerinformation request message. Here, the information request message mayinclude at least one of device ID information, device addressinformation, power level information, and a public key.

The out-band communication module of the wireless power receptionapparatus that receives the information request message may determinewhether a change of the power transfer contract is required. In the casethat a change is required, the out-band communication module of thewireless power reception apparatus may enter the renegotiation phase andchange the power transfer contract (step S1730).

Meanwhile, the out-band communication module of the wireless powerreception apparatus reads or generates the saved power state informationin response to the information request message, and then, transmits aninformation response message including the power state information tothe out-band communication module of the wireless power transmissionapparatus (step S1740). The information response message may include atleast one of device ID information, device address information, powerlevel information, and a public key. The information response messagemay also be called a power information response message.

In the case that the power transfer contract is changed based on therenegotiation phase, the process of saving the power state informationmay be performed again (step S1750), and through this, the power stateinformation is saved. The operation of step S1750 may include theoperation shown in FIG. 15.

Later, the wireless power transmission apparatus and the wireless powerreception apparatus enter the power transfer phase based on the powerstate information which is exchanged therebetween (step S1760).

FIG. 18 is a flowchart illustrating a method for transmitting andreceiving a wireless power based on a process of automatic reconnectionof the out-band communication by the wireless power transmissionapparatus and the wireless power reception apparatus according to stillanother example.

Referring to FIG. 18, while the state in which the out-bandcommunication between the out-band communication module of the wirelesspower transmission apparatus and the out-band communication module ofthe wireless power reception apparatus is maintained (step S1800), theout-band communication is reestablished (step S1810). Here, since theexisting devices which have been connected based on the out-bandcommunication are registered in a whitelist, an automatic reconnectionis available.

The out-band communication module of the wireless power receptionapparatus and the out-band communication module of the wireless powertransmission apparatus perform the automatic reconnection process (stepS1470).

In describing step S1470 in more detail, the out-band communicationmodule of the wireless power transmission apparatus transmits aninformation request message to the out-band communication module of thewireless power reception apparatus to obtain the power state informationwhich is already saved in the wireless power reception apparatus (stepS1820). The information request message may also be called a powerinformation request message. Here, the information request message mayinclude at least one of device ID information, device addressinformation, power level information, and a public key.

Meanwhile, the out-band communication module of the wireless powerreception apparatus reads or generates the saved power state informationin response to the information request message, and then, transmits aninformation response message including the power state information tothe out-band communication module of the wireless power transmissionapparatus (step S1830). The information response message may include atleast one of device ID information, device address information, powerlevel information, and a public key. The information response messagemay also be called a power information response message.

The wireless power transmission apparatus and the wireless powerreception apparatus enter the power calibration phase for calibratingpower related parameters used in power loss to secure reliability of aforeign material detection in the power transfer process (step S1840).The power calibration or power related parameters may be changeddepending on an arrangement state between the wireless powertransmission apparatus and the wireless power reception apparatus.Accordingly, the power calibration phase may be independently performedafter an exchange of the power state information based on the automaticreconnection.

Later, the wireless power transmission apparatus and the wireless powerreception apparatus enter the power transfer phase based on the powerstate information which is exchanged therebetween (step S1850).

The wireless power transmission apparatus according to the embodimentsshown in FIG. 13 to FIG. 18 corresponds to the wireless powertransmission apparatus, the wireless power transmitter or the powertransmitter described with reference to FIG. 1 to FIG. 11. Accordingly,the operation of the wireless power transmission apparatus in thisembodiment may be implemented by one or a combination of two or more ofthe elements of the wireless power transmission apparatus shown in FIG.1 to FIG. 11. For example, the operation of the in-band communicationmodule of the wireless power transmission apparatus may correspond tothe operation of the in-band communication module 121 described withreference to FIG. 4c and FIG. 4 d, and the operation of the out-bandcommunication module of the wireless power transmission apparatus maycorrespond to the operation of the out-band communication module 122described with reference to FIG. 4c and FIG. 4 d. Alternatively, both ofthe operation of the in-band communication module of the wireless powertransmission apparatus and the operation of the out-band communicationmodule of the wireless power transmission apparatus may be performed bythe communication/control unit 120.

Furthermore, the wireless power reception apparatus according to theembodiments shown in FIG. 13 to FIG. 18 corresponds to the wirelesspower reception apparatus, the wireless power receiver, or the powerreceiver described with reference to FIG. 1 to FIG. 11. Accordingly, theoperation of the wireless power reception apparatus in this embodimentmay be implemented by one or a combination of two or more of theelements of the wireless power reception apparatus shown in FIG. 1 toFIG. 11. For example, the operation of the in-band communication moduleof the wireless power reception apparatus may correspond to theoperation of the in-band communication module 221 described withreference to FIG. 4c and FIG. 4 d, and the operation of the out-bandcommunication module of the wireless power reception apparatus maycorrespond to the operation of the out-band communication module 222described with reference to FIG. 4c and FIG. 4 d. Alternatively, both ofthe operation of the in-band communication module of the wireless powerreception apparatus and the operation of the out-band communicationmodule of the wireless power reception apparatus may be performed by thecommunication/control unit 220.

Since the wireless power transmitting method and apparatus or thewireless power receiver and method according to an embodiment of thepresent disclosure do not necessarily include all the elements oroperations, the wireless power transmitter and method and the wirelesspower transmitter and method may be performed with the above-mentionedcomponents or some or all of the operations. Also, embodiments of theabove-described wireless power transmitter and method, or receivingapparatus and method may be performed in combination with each other.Also, each element or operation described above is necessarily performedin the order as described, and an operation described later may beperformed prior to an operation described earlier.

The description above is merely illustrating the technical spirit of thepresent disclosure, and various changes and modifications may be made bythose skilled in the art without departing from the essentialcharacteristics of the present disclosure. Therefore, the embodiments ofthe present disclosure described above may be implemented separately orin combination with each other.

The description above is merely illustrating the technical spirit of thepresent disclosure, and various changes and modifications may be made bythose skilled in the art without departing from the essentialcharacteristics of the present disclosure. Therefore, the embodiments ofthe present disclosure described above may be implemented separately orin combination with each other.

What is claimed is:
 1. A wireless power receiver for receiving wirelesspower based on an out-band communication, comprising: a power pickupcircuit configured to receive wireless power from a wireless powertransmitter based on magnetic coupling with the wireless powertransmitter in an operation frequency and transform an alternate current(AC) signal generated by the wireless power to a direct current (DC)signal; a communication/control circuit configured to be provided withthe DC signal from the power pickup circuit, perform a handover to theout-band communication using a frequency except the operating frequencyin an in-band communication using the operation frequency, transmitpower characteristic information to the wireless power transmitter orreceive the power characteristic information from the wireless powerreceiver based on the out-band communication before entering a powertransfer phase, and perform a process of saving power state informationdetermined during the power transfer phase; and a load configured toreceive the direct current from the power pickup circuit.
 2. Thewireless power receiver of claim 1, wherein the out-band communicationis Bluetooth low energy (BLE), and wherein the communication/controlcircuit transmits or receives the power characteristic information basedon a generic attribute profile (GATT) of the BLE.
 3. The wireless powerreceiver of claim 1, wherein the process of saving the power stateinformation includes: receiving, by the communication/control circuit, asave request message for requesting a saving of the power stateinformation based on the out-band communication from the wireless powertransmitter; and transmitting a save response message for identifyingthe saving of the power state information to the wireless powertransmitter based on the out-band communication.
 4. The wireless powerreceiver of claim 3, wherein the communication/control circuit includesan in-band communication module configured to perform the in-bandcommunication and an out-band communication module configured to performthe out-band communication, and wherein the out-band communicationmodule transfers the power state information to the in-bandcommunication module based on the save response message of powerinformation.
 5. The wireless power receiver of claim 3, wherein the saverequest message includes at least one of device ID information, deviceaddress information, power level information, and a public key.
 6. Thewireless power receiver of claim 1, wherein the communication/controlcircuit is configured to perform a process of exchanging the power stateinformation with the wireless power transmitter in a reconnection aftera disconnection of the out-band communication.
 7. The wireless powerreceiver of claim 6, wherein the process of exchanging the power stateinformation includes: receiving, by the communication/control circuit, apower information request message from the wireless power transmitter;transmitting a power information response message to the wireless powertransmitter; and performing a power calibration.
 8. The wireless powerreceiver of claim 7, wherein the power information response messageincludes at least one of device ID information, device addressinformation, power level information, and a public key.
 9. The wirelesspower receiver of claim 7, wherein the process of exchanging the powerstate information further includes: changing, by thecommunication/control circuit, a power contract by performing arenegotiation phase with the wireless power transmitter based on theout-band communication.
 10. The wireless power receiver of claim 9,wherein the communication/control circuit is configured to perform aprocess of saving updated power state information during therenegotiation phase.
 11. A wireless power transmitter for performing anauthentication based on an out-band communication, comprising: a powerconversion circuit configured to transmit wireless power to a wirelesspower receiver based on magnetic coupling with the wireless powerreceiver in an operation frequency; and a communication/control circuitconfigured to perform a handover to the out-band communication using afrequency except the operating frequency in an in-band communicationusing the operation frequency, receive power characteristic informationfrom the wireless power receiver or transmit power characteristicinformation to the wireless power receiver based on the out-bandcommunication before entering a power transfer phase, and perform aprocess of saving power state information determined during the powertransfer phase.
 12. The wireless power transmitter of claim 11, whereinthe out-band communication is Bluetooth low energy (BLE), and whereinthe communication/control circuit transmits or receives the powercharacteristic information based on a generic attribute profile (GATT)of the BLE.
 13. The wireless power transmitter of claim 11, wherein theprocess of saving the power state information includes: transmitting, bythe communication/control circuit, a save request message for requestinga saving of the power state information based on the out-bandcommunication to the wireless power receiver; and receiving a saveresponse message for identifying the saving of the power stateinformation from the wireless power receiver based on the out-bandcommunication.
 14. The wireless power transmitter of claim 13, whereinthe communication/control circuit includes an in-band communicationmodule configured to perform the in-band communication and an out-bandcommunication module configured to perform the out-band communication,and wherein the out-band communication module transfers the power stateinformation to the in-band communication module based on the saveresponse message of power information.
 15. The wireless powertransmitter of claim 13, wherein the save request message includes atleast one of device ID information, device address information, powerlevel information, and a public key.
 16. The wireless power transmitterof claim 11, wherein the communication/control circuit is configured toperform a process of exchanging the power state information with thewireless power receiver in a reconnection after a disconnection of theout-band communication.
 17. The wireless power transmitter of claim 16,wherein the process of exchanging the power state information includes:transmitting, by the communication/control circuit, a power informationrequest message to the wireless power receiver; receiving a powerinformation response message from the wireless power receiver; andperforming a power calibration.
 18. The wireless power transmitter ofclaim 17, wherein the power information response message includes atleast one of device ID information, device address information, powerlevel information, and a public key.
 19. The wireless power transmitterof claim 17, wherein the process of exchanging the power stateinformation further includes: changing, by the communication/controlcircuit, a power contract by performing a renegotiation phase with thewireless power receiver based on the out-band communication.
 20. Thewireless power transmitter of claim 19, wherein thecommunication/control circuit is configured to perform a process ofsaving updated power state information during the renegotiation phase.